For road racing or when you can't wear a Fast Feet TT Shoecover, this sock saves watts.

Product features

• Castelli's Fast Feet project — for riding in warm conditions
• The foot portion is based on the Castelli Rosso Corsa Sock for in-shoe comfort
• Polyurethane grip strip at top to keep sock in place
• Leg portion constructed with engineered grooved Lycra® to help detach airflow
• Height: 21cm
• Color: Black