The CW-X Pro Shorts offer optimum muscular support for activities with linear movement, such as running. CW-X's patented CW-X Support Web™ provides a suspension system for the hamstrings, reducing workload in the pull phase of the running motion. Combined with targeted variable compression to increase circulation and reduce fatigue, your muscles don¡t have to work as hard over time and your legs will feel fresher.80% Coolmax ®/20% Lycra.UPF 40+.