Waterproof boots, if truly waterproof, cannot breathe therefore, the foot perspires creating dampness. XTRATUF bama-sokkets solve the problem. Removable insulating boot liners combine acrylic fiber with cotton tricot to wick away perspiration and insulate against the cold. Wear one size larger boot when wearing Bama Sockets.They are made in layers which allow perspiration to pass through. This comes in contact with the boot where it condenses to water, which is then absorbed by the outer layer of tough, cotton knit. The inner layer is water resistant acrylic which acts as an insulator against damp and cold. The foot stays dry, warm, and comfortable.