• Castelli's warmest shoe cover for extreme conditions
• GORE-TEX INFINIUM™ WINDSTOPPER® fabric for wind and water protection with maximum breathability
• Polartec® Power Stretch® Pro™ lining to keep you warm
• Thoughtful details ensure high visibility
• YKK® AquaGuard zipper
• High durability materials underfoot

ONE PURPOSE: KEEP YOUR FEET WARMWe set out to create our warmest overshoe ever, which meant rethinking the way booties are made. For windproofing, we opted for GORE-TEX INFINIUM™ WINDSTOPPER® fabric, which also lets more moisture escape than any other windproof fabric. Then we added a second layer of fleece with Polartec® Power Stretch® Pro™, which is unmatched in terms of overall loft. Both layers are thick enough that we had to do a single-layer “wheel well” construction through the toe to keep the fabric from rubbing on the crank. We built the liner high for added warmth and gave reasonable splash protection. We recommend our Venti Soft Sock for maximum warmth.