The OS1st CS6 Performance Calf Sleeves provide medical grade orthopedic support. Our patent pending Compression Zone Technology provides pain relief and preventative support. CS6 Performance Calf Sleeves provide athletes with relief from calf pain and injury. Find prevention and relief from muscle cramps, venous insufficiency, Achilles tendinitis, and shin splints.Easy, moisture wicking slip-on therapy. OS1st compression zone technology boosts circulation, protects from injury, eases shin splints, and provides increased muscular support reducing impact vibration. Easy-on anatomical fit is designed to be worn before, during, or after any activity.