The insulated evolution of Frictionless Wetsox, the Frictionless Thermals offer a 1.5MM neoprene core for insulation where you'll want it most. No need to size up boots. Channel-Lined interior for increased warmth and comfort. They fit over your calf so they're great for layering and insulation and won't slip or bunch. Wear these with split toe boots and keep your feet warm.