OS1st has greatly improved upon the light bracing base layer that can be worn during any activity or sport, such as running or hiking, for added support and compression without compromising comfort and flexibility/mobility. Their compression zone technology mimics kinesiology taping techniques and combines the benefits of medical grade orthopaedic support with graduated compression. The material is highly breathable and thin enough to not be restrictive or cumbersome during activity. Get back out on the Eastern Sierra trail quicker post-injury with an Os1st bracing sleeve!The OS1st Performance Calf Sleeve helps boost circulation, protects from injury, eases shin splints and provides increased muscular support. This sleeve comes in small, medium, large, and extra-large for an optimal fit.