Introducing Compression Sale Extreme! Featuring the most effective and lightweight materials in the right areas of the human anatomy is a mixture of both art and science. CSX Compression Sport Socks and Compression Calf Sleeves use two different levels of compression, and are designed to give athletes and active individuals the decisive edge in performance, injury reduction and recovery. Built with the greatest support at the ankle that reduces gradually up the leg, they work to reduce the diameter of the superficial veins in the lower leg and thus help improve blood flow. Improved flow can help protect, energize, and renew tired muscles.