Breakthrough product specifically designed for comfort, fit, protection and breathability. OS1st TA4 Thin Air^TM Performance Socks feature never before applied technology to keep your feet cool and protected during any activity.  Created using 200n medical grade machinery and materials we are able to build in comfort, durability and blister protection, yet with the thinnest upper foot profile ever made. The “Thin Skin^TM” construction with uniquely positioned lift-bars, maximizes air-flow achieving a cooling sensation to your feet.  Our OS1st manufacturing technology has been leveraged to create the most unique performance socks ever!