Winter shoecover Castelli Estremo are our warmest. Thanks to the Polartec inside and Gore-tex infinum, we have achieved the maximum temperature comfort that is needed in the most difficult conditions.

• Compatible with road racing shoes (not suitable for MTB)
• Very warm design for cold winter days
• Ideal to use below 10 °C

Product features:

• Castelli's warmest shoecover for extreme conditions
• GORE-TEX INFINIUM™ WINDSTOPPER® fabric for windproof water protection with maximum breathability
• Polartec® Power Stretch® Pro™ lining to keep you warm
• Reflective details provide high visibility
• YKK® AquaGuard® zipper
• High-durability material under foot
• Temperature comfort: -10° - 5 °C / 8° - 41 °F

One goal: keep your feet warm

• We set out to create our warmest bootie ever, which meant rethinking how booties are made. For the windproofing we went with GORE-TEX INFINIUM™ WINDSTOPPER® fleece-backed fabric, which also lets more moisture escape than any other windproof fabric. Then we added a second fleece layer with Polartec® Power Stretch® Pro™, which is unrivaled in overall loft. The two layers are thick enough that we had to do a wheel well single-layer construction by the ball of the foot to prevent the fabric from rubbing on the crank. We made the bootie high for extra warmth and gave reasonable splash protection.

Material composition:

• Outer main material: 100 % polyester
• Main inner material: 92 % polyester, 8 % elastane
• Outsole: 47 % polyurethane, 36 % polyester, 17 % cotton
• Lining: 88 % polyester, 12 % elastane