Thinsulate is a brand of insulation used in jackets, boots, gloves, hats, and pants. A specific type, called 3M Thinsulate, keeps you warm by trapping air molecules between you and the outside. The more air a material traps, the warmer you’ll be. Unique microfibers make up the Thinsulate insulation, and these fibers are finer than most other synthetic fibers or natural insulation, so Thinsulate traps more air in less space. This makes it a better insulator, and it doesn’t need all the extra bulk to keep you warm. It’s breathable, moisture-resistant, and both machine washable and dry-cleanable.