This glove liner is soft, comfortable, and easily fits under other gloves for added warmth. Made with our HEATR(R) fabric which is a high-tech material developed by WSI that helps keep you up to 40% warmer than other materials on the market. Fibers that are integrated within the fabric expand and heat up as they come into contact with the skin. Since the fibers are integrated in the fabric, they will not wash out. 100% Made in USA