OS1st TA6 Thin AirTM Performance Calf Sleeves feature never before applied technology to keep your legs cool and protected during any activity. Created using 400n medical grade machinery and materials we are able to build in ease of use, comfort, and durability with the thinnest leg fabric profile ever made! The "Thin SkinTM" construction maximizes air-flow achieving a cooling sensation to your legs thereby increasing stamina and endurance.