Thinsulate™ is a trademark of the 3M Corporation, for a type of synthetic fiber thermal insulation used in clothing. Thinsulate™ fibers are about 15 micrometres in diameter, which is thinner than the polyester fibers normally used in insulation for clothing such as gloves or winter jackets. The manufacturer claims that, for a given thickness of material, Thinsulate™ provides 1 to 1.5 times the insulation of duck down, while being much less water-absorbent and much more resistant to crushing. Thinsulate™ insulation works by trapping air molecules between you and the outside. The more air a material traps in a given space, the greater its insulating value. Because the microfibers in Thinsulate™ insulation are far finer than other fibers, they trap more air in less space, which naturally makes it a better insulator. Thinsulate™ is breathable, moisture resistant and machine washable.