Castelli Fast Feet 4 Socks - white 001

Fast Feet 4 Socks There are many so-called aero socks out there. But the Castelli Fast Feet 4 sock has the development and test results to prove that it lives up to its name. The few socks that have been tested were likely evaluated using a static test while at rest, because that’s easier. But since a foot is constantly in motion, we developed a device that simulates the movement of the lower leg. And we conducted tests with real cyclists to validate the results. This sock can save 2 watts at 50 km/h. The latest version features an updated cuff fit for greater comfort and aerodynamics. Features of the Castelli Fast Feet 4 Socks: Castelli’s Fast Feet project – for maximum aerodynamics Foot area based on the Castelli Rosso Corsa socks for comfort inside the shoe Polyurethane grip strips at the top to prevent the sock from slipping Leg section made of specially developed, grooved Lycra® to optimize airflow Material Main fabric: 85% polyester, 15% elastane Ankle: 82% polyester, 18% elastane