What Our Gearhead(R) Experts Are Saying: "This sock has been a game-changer on my cold-weather rides. It's super warm without being bulky, and the Primaloft stays dry even when I start to sweat. If wool isn't your thing, this is the perfect alternative." The Castelli Como 15 Thermal Sock is built for cyclists who want reliable warmth without the bulk-especially when wool isn't an option. Made with a performance-driven blend of Primaloft(R) and polypropylene, this sock keeps our feet warm and dry through cold-weather training and long, wet rides. A terry-cloth bottom provides extra loft and insulation underfoot, while thoughtful features like smooth toe seams, directional arch compression, and a reinforced heel keep us comfortable and supported. The 15cm cuff adds coverage and stays securely in place without pinching. It's everything we want in a winter sock-except the wool.