ONLY ONE GOAL: KEEP YOUR FOOT WARM We have really committed to creating the warmest shoe covers ever, to do this we had to rethink how the shoe covers are made. For wind protection, we chose GORE-TEX INFINIUM™ WINDSTOPPER® slightly brushed fabric, which also allows a greater amount of moisture to escape than any other wind-proof fabric. Then we added a second soft layer of Polartec® Power Stretch® Pro™, which is unrivaled in terms of softness and thermal insulation. Because the two layers are thick enough, we had to reduce one front of the foot to a single layer to prevent the fabric from getting damaged by rubbing with the crank. We made these shoe covers taller to be even warmer and also gave it good protection from water splashes raised by the wheel. We recommend our Venti Soft socks to stay even warmer.