"Ruck all day with this cooling master. The OS1st TA6 Thin Air Calf Sleeves feature never before applied technology that aids in recovery, boosts circulation and prevents overheating for maximum performance. Easy on fit with the thinnest leg fabric profile ever made and created using 400n medical grade machinery, ""Thin Skin™"" construction maximizes air-flow and creates a cooling effect for your legs. With 6 compression zones for comfort and support, you will increase stamina and endurance during any activity."