Thinsulate® is a low-bulk insulation used in footwear and gloves made of fibers about ten times smaller than the fibers of most other synthetic insulations. The fibers are more efficient at trapping air and more effective at maintaining warmth. More fibers can be packed into the same space, where they can retain more of the body’s radiant heat. In terms of bulk, Thinsulate® fibers are 1½ times more effective than down. The fibers are not affected by repeated washings or dry cleanings.