The Castelli Re-Cycle Thermal 18 Socks in Black are crafted for cyclists who value sustainability and comfort. Made entirely from post-consumer recycled polyester from plastic bottles, these socks feature a midweight design that offers warmth without added bulk. The 18 cm cuff provides extra coverage, ideal for cooler fall and early spring rides. With a regular fit, these socks combine performance with eco-friendliness, making them an excellent choice for environmentally conscious athletes.