This pure, natural rubber is mixed with our own secret recipe, making the fundamental composition 80% pure, natural rubber and 20% secret recipe. Entirely PVC-free, our boots contain no animal by-products. The result is a sturdy and reliable companion for every day, rain or snow. TFull shank and arch support boot soels are rated to -40c, Ithe uppers withstand temperatures down to -20c . Laces are 100% cotton.