Castelli Size Chart Free is fast thanks to the water-repellent fabrics that are also wind tunnel tested for on-bike speed. And Free helps you perform at your maximum by providing just- right muscle support and keeping your body cool. High-capacity pockets provide ample room for your essentials, and the hook fastener will prevent your top from riding up during the swim and bike. Even the back fabric shows the engineering in this garment: wind tunnel tested for on-bike speed, it also provides exceptional cooling while offering UPF 16 protection that blocks 94% of UV rays. Features: - SpeedFreak ventilated race fabric on front - Velocity mesh back gives wind-tunnel-proven speed on the bike - Hook fastener at lower back to connect to shorts to prevent riding up during swim or bike leg - YKK(R) Camlock zipper - FreeAero 2 hydro- and aero-optimized pockets - Soft-finish armholes to reduce chafing - 2 back pockets