Methylsiloxane polymer didn’t enter the world of materials chemistry by accident. People have tinkered with silicon and oxygen backbones since the early 20th century, chasing something that can take heat, stick around in harsh conditions, and stay flexible when most plastics would crumble. Harold Rochow and Eugene Rochow ended up cracking the code on silicone synthesis in the 1940s, leasing out a chemistry that would eventually show up in everything from oven mitts to microchips. Big chemistry firms started scaling up methylsiloxane production in the 1950s, and from there, it took on a life of its own. Once manufacturers saw how well this stuff shrugged off moisture and UV light, there was no going back. The push for industrial resilience after World War II put methylsiloxanes in high demand, locking them in as a go-to choice for companies wanting reliability.
Walk into a hardware store, pick up a tube labeled “silicone sealant.” Unscrew the jar of “dimethicone” in an old-school cosmetics cabinet. Scour lab supply catalogs and there’s “polydimethylsiloxane”—PDMS. They’re all trading on the backbone of methylsiloxane polymers. Labels change, trade names multiply (Dow Corning, Wacker, Shin-Etsu, Momentive), and the polymers come out as oils, elastomers, fluids, or resins, but the toolkit behind them still leans on the same repeating Si–O units capped with methyl groups. These polymers don’t lock themselves into neat categories; you can spot them in contact lenses, medical tubing, anti-foaming agents, waterproof sprays, high-temperature lubricants, and even baking molds. The chameleon act comes from tweaks in chain lengths or how the polymer network is crosslinked, letting one backbone stretch into more end uses than most plastics can touch.
You could pour out a sample of polydimethylsiloxane and see that slick, almost slippery feel right away. This stuff refuses to freeze even though most other organics would crack. It shrugs off creeps from sunlight and doesn’t even flinch at ozone or polar solvents. Its molecules coil around each other in a way that makes mechanical flexibility second nature, stretching rubbery without snapping. At the same time, the silicon-oxygen backbone spits in the face of heat and UV—the backbone just doesn’t break down easily. Its surface takes in little water, so water beads roll right off. Silicone oils flow smoothly, with viscosities that stay steady across temperature swings much wider than mineral oils can manage. All of this opens doors to engineering problems that would stump carbon chains alone.
Check a drum of methylsiloxane polymer and you’ll see detailed viscosity grades, volatility, polymerization degree, and in some cases, the amount of residual silanol (Si-OH) left over from manufacture. Silicone elastomer grades specify durometer hardness, elongation at break, tensile strength, and how much they can stretch before losing their snap. Some labels carry purity levels measured in parts-per-million for medical or food use—buyers demand documentation, and inspectors check compliance with ISO, FDA, REACH, or similar regulation sets. In paints and coatings, standards focus on volatility and resistance to yellowing or outgassing, so no manufacturer wants gaps in certification trails.
Silicon sits deep in the Earth. Chemists dig up silica sand and process it with methyl chloride using a copper catalyst—what comes out is a stew of methylchlorosilanes. Purification trims these to the right fractions before the real magic: hydrolysis and condensation, dropping chlorine atoms and stitching together a line of alternating silicon and oxygen atoms, methyls branching off the side. The resulting oligomers or polymers get their chain lengths dialed in by careful distillation and controlled reaction times. Crosslinking (known as “curing”) flips these liquid or gum-like materials into tough, rubbery solids. Add some peroxide, platinum, or tin catalyst, and watch the snarl of molecules knit into something that lasts for decades.
Base methylsiloxane gives you a starting point, but chemistry rarely sits still. Tweaks roll in by adding functional groups at chain ends or along the backbone. Hydrosilylation lets you snap on vinyl, phenyl, or even fluorinated groups, opening doors to higher-temperature stability, better optical clarity, or stronger adhesion. You can co-polymerize with other siloxanes to carve out niche properties: some tweak the modulus, others tune permeability. Grafting in bulky or sticky groups can help methylsiloxane stick to glass, metal, or organic polymers. Any time durability, slipperiness, or flexibility need to be tailored, chemists roll out a new synthetic route.
If two chemists start talking shop about methylsiloxane, sooner or later, someone says “PDMS,” “dimethylsiloxane,” or “silicone polymer.” Go through textbooks and you’ll see “polydimethylsiloxane” the most. In pharma and cosmetics, the bottle almost always reads “dimethicone.” Catalogues for research-grade material often brandish the exact methylsiloxane chain length—“trimethylsiloxy-terminated polydimethylsiloxane” shows up for specific molecular weights. There’s a library of abbreviations for special-use versions, but the structure never strays far from Si–O– backbone dressed in methyl groups.
Every lab and factory in the world keeps a close eye on how polymers get stored and processed. Methylsiloxane polymers rank as one of the tamer materials out there in most grades. They resist breakdown, don’t catch fire easily, and show low skin irritation at consumer levels. Workplaces still train crews to avoid inhaling fine mist or dust, since particles can be a nuisance for lungs. Large-scale reactors burn off trace byproducts or silanol fumes with scrubbing towers, keeping any volatile organic content in check. Production lines stress cleanliness, prevention of cross-contamination, and proper labeling because mislabeling grades—especially in medical or food work—could cause more than just paperwork headaches. Continuous review of MSDS sheets, local regulations, and emergency procedures stays part of routine safety culture.
Take a look around any modern city and this family of polymers stands out for its utility. In electronics, PDMS backs flexible circuits, potting compounds, and insulation. Hospitals count on medical-grade silicones for catheters, heart pump tubing, and wound dressings because bacteria struggle to colonize the surface and cleaning doesn’t shorten lifespan. Food companies rely on silicone for non-stick bakeware and defoaming agents that don’t break down during cooking. Construction firms reach for sealants and weatherproofing based on methylsiloxane polymers to keep joints tight for years—often outlasting adjacent building materials. Car makers depend on high-temperature silicone hoses under the hood, where hydrocarbon rubbers would fail. Researchers choose PDMS to cast microfluidic chips, building small-scale pathways for biological or chemical tests in labs worldwide. Whenever long life, chemical neutrality, and flexibility overlap, methylsiloxane earns a permanent home.
Fresh advances in methylsiloxane chemistry keep bubbling up. Materials scientists chase better adhesion to organic substrates by engineering side chains that bridge the gap between inorganic silicon and carbon-based surfaces. Bioengineers design PDMS formulations for new biocompatibility profiles, allowing implants that promote cell growth or sensors that sit harmlessly in tissue. Researchers in microfabrication hone the mold-release and curing speed of PDMS to build ever-tinier biomedical and electronics components. Teams study how nanoparticles or hybrid additives—like graphene or silver—can blend with methylsiloxane to yield conductivity, antimicrobial action, or smart-response surfaces. Environmental teams seek greener cures and lower-emission processes that match performance without leaving behind persistent byproducts. Each development taps a huge base of published studies, patents, and trial reports, so progress rarely stops for long.
Lab tests keep shine on methylsiloxane’s safety reputation, especially in the context of consumer exposure. Studies find extremely low acute toxicity by ingestion or skin contact in the vast majority of cases, making silicone-based products a mainstay in sensitive applications from healthcare to food contact. Still, regulatory scientists dig into questions about persistence and breakdown in sewage and soil, since certain methylsiloxanes resist microbial digestion. Reports from environmental agencies raise flags when persistent, low-volatile variants show up in aquatic systems, collecting in sediments and sometimes in the tissues of wildlife. This has prompted fresh rounds of study, more stringent wastewater controls, and calls for clear labeling on non-degradable grades. Most experts sort methylsiloxanes into the ‘lowest hazard’ bracket of synthetic polymers, but pressure mounts to ensure legacy products don’t outlive their usefulness in open environments.
Looking ahead, it feels like methylsiloxane polymers have room to push into smart materials—coatings that switch properties on cue, wearable devices that flex with the skin, or membranes that selectively manage gas or fluid transport. Sustainability goals force manufacturers to find processes using fewer hazardous reagents, new renewable fillers, or strategies that snap the Si–O chain into recyclable fragments at the end of service life. Demand for medical-grade silicones will keep climbing as populations age and look for safer, longer-lasting implants. Microelectronics keeps raising the bar for dielectric performance in ever-thinner insulating layers. The challenge lies in balancing chemical durability with better end-of-life management, so future methylsiloxane products don’t become a headache for ecosystems or waste streams. All the current research points to a future where methylsiloxane doesn’t just serve as an old standby, but keeps shaping innovations just over the horizon.
This material shows up everywhere: bathrooms, kitchens, car doors, and even shampoo bottles. Methylsiloxane polymer, sometimes called polydimethylsiloxane (PDMS), belongs to the silicone family. Its backbone is made from silicon and oxygen, decked out with lots of methyl side groups. Sounds technical, but most people recognize it as that flexible, clear gel or rubber that refuses to dry out or crack.
Working in construction, I’ve applied more silicone sealant than I can remember. Bathroom caulk, window seals, water-resistant barriers—all crafted from methylsiloxane polymers. Their resistance to weather, mold, and sunlight puts them ahead of latex or acrylics. This stuff doesn’t stiffen up after a rough winter or a humid summer, which slashes repair bills. It’s no surprise building codes now push for silicone solutions in leak-prone areas.
Hospitals and clinics run through mountains of lubricants. Methylsiloxane shows up on syringe plungers, catheter coatings, and implantable devices. Its slick, non-reactive nature protects patients from nasty infections and keeps bloodstream devices gliding instead of dragging. I once had a friend with a pacemaker, and the doctor explained that a methylsiloxane layer helps stop scar tissue from clinging to delicate wires.
Look at the ingredient list on conditioners, lotions, or even processed foods. Food-grade PDMS sneaks into frying oils so they don’t foam all over the kitchen. In toothpaste, it stops the paste from drying out. My grandmother always grumbled her hair serum worked better than anything from the eighties — all the shine came from a small dose of methylsiloxane polymers. Despite the tongue-twisting name, it doesn’t build up on skin or hair. It rinses out, lending a silky finish and a refreshing lack of greasiness.
Inside the electronics repair shop, I noticed every wire crimp and circuit board coating used clear silicone. Engineers trust methylsiloxane for its strong insulation and its ability to shrug off heat. High-end cell phones often get a rain-repelling coating of this polymer. According to industry analysis, manufacturers prize it for wires, keyboards, and batteries because it prevents short circuits caused by sweat or dust.
Methylsiloxane isn’t perfect. People started asking what happens when it gets dumped or washed down drains. Some researchers in Europe found that certain forms build up in lake sediment and fish tissue. It doesn’t break down like soap or vegetable oil. Manufacturers have begun tweaking the chemistry to help the polymer decompose faster. This push for greener silicone additives could reshape both personal care and packaging industries in coming years.
For families and workers who handle the stuff, allergies or sensitivities remain almost unheard of. Still, it gets smart to use gloves or ventilate a room when laying down sealants for hours on end. Everyday people rarely face risks with small exposures, but anyone curious about the latest research can check studies from the World Health Organization or their country’s environmental health agency.
Engineers and chemists dream up ways for methylsiloxane to serve without sticking around forever. Recent academic studies in the US and China suggest adding biodegradable side chains. Some green chemistry startups show real promise, working with universities and investors to tweak the building blocks of silicone, aiming for stronger bonds inside the product and weaker ones outside in the environment.
Anyone checking labels on shampoos, lotions, or even frying pan coatings will spot something called methylsiloxane polymer. It’s a type of silicone, one that brings smooth textures, water resistance, and that famous silky feel. I’ve used skin care products with this ingredient for years. You’ll see it listed as dimethicone or cyclopentasiloxane on most bottles in supermarkets.
Touching this stuff doesn’t usually trigger allergies or breakouts. The big beauty brands put a lot of money into making sure people don’t end up with rashes or red skin. Research backs this up. Health Canada and the U.S. Food and Drug Administration both allow methylsiloxane polymers in cosmetics and say they’re safe for most people. Still, a few users might end up with mild irritation, but those cases seem rare.
I’ve read reports from medical journals and watched how the public responds. The eyes and skin act as our biggest defense, and methylsiloxane tends to sit on the surface rather than getting absorbed. It forms a barrier, which is why it’s a hero in diaper creams and ointments. Journal articles from the National Institutes of Health say these polymers don’t build up in our bodies. Their large molecular structure stops them from getting too deep through the skin.
You’ll find talk online about cyclic siloxanes causing problems. Some forms—like D4 and D5—show signs of concern if they reach high levels in animals, but those cases don't reflect how cosmetics are used. In Europe, strict rules limit these ingredients in sprays or deodorants, especially when people breathe them in tiny airborne particles. So far, studies show exposure from using a regular lotion or shampoo is way lower than the risky amounts. Trustworthy sources make it clear: sticking with brands that follow safety laws protects anyone who uses these products as directed.
Big beauty brands and household cleaners run long safety tests, and governments set clear rules for methylsiloxane polymers. That doesn’t mean people should tune out warning signs from their own skin. I tell friends, watch for changes and ask a doctor if a rash shows up. Reading up on scientific findings instead of social media rumors helps clear up worries.
Companies are listening. Green chemistry groups keep pushing for new testing methods and safer alternatives for people with sensitivities. Brands respond by swapping out certain types of methylsiloxane in favor of ones with stronger evidence behind them. Anyone looking for “clean beauty” can now spot silicone-free products on store shelves more easily than five years ago.
Pay attention to how skin reacts and report anything odd. Read label ingredients and stick to products made for someone’s skin type. Anyone worried about environmental impact or chemical buildup can find choices that skip questionable silicone forms. As long as brands and scientists keep talking and consumers stay curious, the market stays safer and more transparent for everyone.
Anyone who has handled a kitchen spatula with a slick, rubbery handle has come across methylsiloxane polymer, even without knowing it. Chemists call it polydimethylsiloxane or PDMS. It stands out from other synthetic materials because of an unusual combination: flexibility, water repellency, thermal stability, and a silky-smooth feel.
As someone who has wrestled with sticky adhesives and watched commercial coatings fail after a few seasons, I see one thing people often overlook. This polymer doesn’t just shed water—it resists stains, dust, UV rays, and even the sticky hands of a toddler. Spills bead up. Food rarely clings. The surface wipes clean, making it a favorite for bakeware, tubing, gaskets, medical devices—just about anything that benefits from staying both tough and clean.
The backbone of methylsiloxane polymer is built on alternating silicon and oxygen atoms with simple methyl groups sticking out like tiny bristles. This structure lets the long chains twist and flex, which explains the “stretch without break” property that makes these materials bounce back even after bending or squishing. This flexibility goes far beyond what you’d expect from a plastic. Even after hundreds of cycles of compression, the material snaps back into shape. It doesn’t grow brittle in the sun or crack in the cold, which matters if you’re relying on stability in industrial windows, automotive seals, or medical tubing that faces sterilization over and over.
Researchers point to a high glass transition temperature, meaning methylsiloxane stays rubbery and doesn’t harden up in cold weather. Most plastics get loud and crunchy in the freezer; PDMS simply shrugs and carries on.
Back in high school chemistry, I watched classmates fry cheap plastic beakers on a Bunsen burner, but PDMS would have fared much better. It’s built to stand up to high heat—usually up to 200°C or even 300°C, depending on the crosslinking. It doesn’t melt and ooze into a puddle. In fact, heat barely nudges its physical structure, so it stays put in automotive components right next to engines, or on the wings of airplanes where temperatures plummet and soar.
Skiers and arctic researchers take advantage of this cold-proof ability as well. Methylsiloxane won’t turn brittle and snap in freezing weather, so outdoor gear, frigid laboratory tubes, or satellites circling Earth can all lean on its resilience.
Bakeware companies boast about using “platinum-cured silicone.” This is PDMS at its purest. It doesn’t give off harmful fumes, doesn’t react with food, and doesn’t let bacteria stick easily—good reasons hospitals and bakers alike turn to it. Regulatory agencies consider it non-toxic and biocompatible. The FDA and European authorities both grant approvals across a wide range of uses, from food molds to baby bottle nipples. That trust hasn’t come easy—decades of studies back up these approvals.
Adhesion with PDMS is its odd quirk. By nature, the surface is so slick that most glues don’t stick, which is great for anti-graffiti coatings but a problem if you need to bond it to another material. Scientists have gotten creative. They rough up the surface, zap it with plasma, or use special primers to build a bridge for adhesives. This challenge kicked off a wave of research, even inspiring whole start-ups dedicated to better silicone bonding.
Methylsiloxane’s properties offer so much potential in everything from medical technology to sustainable coatings. Recycling remains a headache since traditional systems can’t handle silicone-based materials without specialized processes. More investments in clean, scalable recycling will unlock even greater benefits while shrinking the environmental footprint. Methylsiloxane isn’t perfect, but it has earned its reputation in both kitchens and laboratories—sturdy, dependable, and sometimes a little too slippery for its own good.
Methylsiloxane polymer, mostly referred to as silicone, shows up often in both household products and heavy-duty industrial gear. Folks notice it in cookware, medical tubing, electrical insulation, even car gaskets. The reason engineers and designers reach for this material isn’t just flexibility—it’s how silicone holds up when heat turns up the pressure.
Silicone-based methylsiloxane doesn't melt or break down until temperatures soar past 200°C, sometimes hitting the 300°C mark without losing its basic shape or chemical structure. Most plastics start to warp or release fumes long before that point. I’ve tossed silicone bakeware straight from a freezer into a hot oven more times than I can count, and it bounces back every single time. Gasket makers choose these polymers since engines push constant heat, and parts need to survive that abuse for years.
Data from industrial tests provides evidence: methylsiloxane elastomers keep up their properties even after hundreds of hours at 200°C. In electronics, manufacturers rely on this for insulating delicate parts, preventing sudden electrical failures caused by overheating. Once temperatures go beyond ordinary limits, some plastics char, others turn brittle. Silicone shrugs it off.
This resilience ties back to its backbone structure. Where most organic polymers falter, the silicon-oxygen link in methylsiloxane keeps its cool. These molecules resist breaking down, which means less risk for fire and fewer toxins if flames do start. In fire safety, that changes outcomes fast. Hospital techs want ventilator hoses and seals that stay stable—lives depend on that consistency. Aviation and automotive industries trust methylsiloxane for seals and connectors close to engines and exhaust lines, because safety comes first, and reliability cuts down costly recalls.
No material gets a free pass in every scenario. Silicones can lose strength if exposed for a long time at the very top of their range, and high pressure plus heat speeds up aging. Oils, fuels, and acids can slowly nibble away at the polymer, especially at hot spots. Even a silicone spatula shows cracks or discoloration after years over a stove. In industrial setups, adding extra fillers or adjusting the polymer recipe helps protect against some of that slow wear. Still, nobody expects an engine seal to last forever without maintenance.
Laboratories keep pushing the boundaries, blending methylsiloxane with advanced ceramics or adding unique fillers like carbon black. These tweaks aim to stretch the useful temperature range or boost chemical resistance for the next generation of EV components and medical tech. Regular quality checks and new manufacturing standards have become the norm, so that every batch shipped keeps consistent performance.
For most applications facing heat, methylsiloxane remains a go-to pick—whether it’s your home oven mitt, a fuel-cell vehicle, or the wiring running above your head on a plane ride. Awareness of real-world stress factors shapes how long these polymers keep doing their job. Smart engineering and steady oversight ensure these materials meet the challenges we throw at them every day.
Anyone who’s handled specialty chemicals knows you can’t take shortcuts, especially with methylsiloxane polymer. You’re dealing with something built for flexibility, resilience, and chemical stability in industries from electronics to construction. Many folks don’t realize just how quickly light, air, or sloppy handling can ruin a good batch. That translates into safety risks at best and wasted money at worst.
The first thing that jumps out from technical data sheets, and from anyone with lab experience, is temperature. Storing methylsiloxane polymer near sources of heat shortens its shelf life and may cause the tubes or drums to deform. Room temperature — ideally around 20°C to 25°C — works best. Stashing it next to boilers, ovens, or even large windows under the sun cuts its life short, and sometimes turns the whole thing into a gummy mess.
Humidity brings its own problems. Moisture reacts with silicones, and although methylsiloxane is more forgiving than some, water in storage triggers hydrolysis. That means cloudiness, change in viscosity, and eventually an expensive sludge that won’t do its job. So keep those storage rooms dry, with reliable seals on every container.
From years in labs and working with maintenance teams, one overlooked enemy: oxygen. Exposure to the open air speeds up degradation much faster than most new warehouse workers expect. Good practice always means closing containers right after use, and checking for worn gaskets or cracks. Even a small tear in a drum liner means the whole thing can spoil by the next week.
Smaller packaging helps, too. Instead of pulling gallons from one big drum that gets opened a dozen times, splitting the stock into smaller, tightly sealed units makes it far easier to minimize risk. And it keeps inventories easier to rotate — nobody wants to discover an ancient, yellowed tub hiding at the back of a stockroom.
One overlooked vulnerability: sunlight and UV exposure. Polymers start breaking down after too much sunlight, no matter how tough they seem at first. I’ve seen stores where products near a window turned brittle before their expiration date. A windowless, controlled storage area is best — even far from roll-up doors where stray daylight sneaks in.
Electric sparks and open flames should never show up anywhere near these storage areas. Silicones sound safe, but additives sometimes burn or off-gas chemicals you absolutely don’t want on your conscience. Using dedicated, spark-proof tools and signage in storage rooms goes a long way toward prevention. Good training turns this from a headache to a checklist item.
Inventory turns into a mess if nobody tracks expiration dates. Methylsiloxane polymer usually sits on the shelf for six to twelve months, but only with airtight, climate-controlled storage. Putting newer shipments behind older ones forces first-in, first-out practices without much fuss. A good label and date on every package sets everyone up for success and stops accidents before they start.
Piling unrelated chemicals, dirty rags, or leaky lubricants next to stored polymer helps nobody. Cross-contamination silently eats at product quality. Dedicating a spot that stays clean pays for itself with fewer failures down the line. One forgotten open paint can or a leaky bottle of cleaner really can contaminate a whole shelf in a single hot weekend.
Nothing beats putting in place these basic habits: cool, dry rooms; air-tight containers; dark corners; fire safety; and smart rotation. These steps build confidence with customers, regulatory inspectors, and anyone on the shop floor who doesn’t want ruined materials or safety complaints. I’ve seen these routines save small businesses from both expensive recalls and stubborn insurance claims. Solid storage keeps quality steady, business running, and everyone on the right side of the rules.
| Names | |
| Preferred IUPAC name | poly(dimethylsiloxane) |
| Other names |
Dimethicone Polydimethylsiloxane PDMS Siloxane polymer Silicone oil |
| Pronunciation | /ˌmɛθ.ɪl.sɪˈlɒk.seɪn ˈpɒl.ɪ.mər/ |
| Identifiers | |
| CAS Number | 63148-62-9 |
| 3D model (JSmol) | `CC[Si](C)OC[Si](C)OC[Si](C)OC` |
| Beilstein Reference | 1461256 |
| ChEBI | CHEBI:88841 |
| ChEMBL | CHEMBL1909507 |
| ChemSpider | 563085 |
| DrugBank | DB11140 |
| ECHA InfoCard | 100.118.785 |
| EC Number | 63148-62-9 |
| Gmelin Reference | 24939 |
| KEGG | C18647 |
| MeSH | D014010 |
| PubChem CID | 24761 |
| RTECS number | VV7310000 |
| UNII | 4RWS1D3D4F |
| UN number | UN1993 |
| Properties | |
| Chemical formula | (C2H6OSi)n |
| Appearance | Colorless transparent liquid |
| Odor | Odorless |
| Density | 0.970 g/cm3 |
| Solubility in water | Insoluble |
| log P | 2.0 |
| Vapor pressure | Negligible |
| Magnetic susceptibility (χ) | -6.9e-6 cm³/mol |
| Refractive index (nD) | 1.403 |
| Viscosity | 1500-2500 cP |
| Dipole moment | 0.0000 D |
| Thermochemistry | |
| Std molar entropy (S⦵298) | 336.0 J·mol⁻¹·K⁻¹ |
| Std enthalpy of formation (ΔfH⦵298) | -696 kJ/mol |
| Std enthalpy of combustion (ΔcH⦵298) | -736.6 kJ/mol |
| Pharmacology | |
| ATC code | D11AX19 |
| Hazards | |
| GHS labelling | GHS07, GHS08 |
| Pictograms | GHS07,GHS08 |
| Signal word | Warning |
| Hazard statements | Hazard statements: H226, H315, H319, H336 |
| Precautionary statements | P210, P233, P403+P235, P501 |
| NFPA 704 (fire diamond) | 1-1-0 |
| Flash point | > 225 °C |
| Autoignition temperature | 500°C |
| LD50 (median dose) | > 49.5 g/kg (rat, oral) |
| PEL (Permissible) | PEL: 5 mg/m³ |
| REL (Recommended) | less than 10 mg/m³ |
| Related compounds | |
| Related compounds |
Polydimethylsiloxane Dimethicone Silicone oil Trimethylsiloxy-terminated siloxane Siloxane oligomers Silicone rubber |
