Cold Weather Heavyweight Wool Insoles. 5/16" (inches) thick. 3 layer construction for warmth & comfort. Place inside shoes or boots to give your feet that extra warmth sometimes necessary in cold weather. Comfortable fit. Made in Canada. Wool felt: 50/50% polypropylene/polyester. Interior: polyurethane. Cold weather heavyweight wool felt insoles. This product is GSA Compliant. Medium measures 11 1/8" x 4" (inches) at its longest and widest point. The large measure 12.5" x 4 3/8" at its longest and widest point.