![Castelli Fast Feet 2 Cycling Sock Castelli Fast Feet 2 Cycling Sock](https://cdn11.bigcommerce.com/s-c0cjv/images/stencil/300x300/products/38713/60958/60958__99634.1679700272.jpg?c=2)
Ultimate aero accessory to cover shoes and calves for reduced drag.
- For athletes searching for that last bit of performance gain
- Wind tunnel tests showed up to a 6-watt savings at 45 km/h compared to a normal sock
- Silicone-coated stretch fabric over the shoe smooths out airflow
- Engineered grooved Lycra® on ankle portion helps detach airflow
- Flat polyurethane tape at top to keep shoecover in place
- YKK® zipper