What Our Gearhead® Experts Are Saying:"I love the A/C 18 Sock for summer rides. It’s breathable, lightweight, and durable enough to handle long training sessions in the heat."When the heat is on, the Castelli A/C 18 Sock helps us keep our cool. Built for the hottest days on the bike, this ultralight sock features a ribbed texture for the perfect balance of breathability and durability. Its nylon-elastane blend wicks moisture efficiently while maintaining a snug, race-ready fit. The 18cm cuff adds a touch of classic style, making this sock a staple for warm-weather training and racing.