The Klein Tools 60509 Performance Thermal Socks with merino wool regulate temperature, wick-away moisture, and reduce odor. These mid-length socks are made in the USA, have a seamless toe closure for comfort, and a reinforced heel for abrasion resistance. Mesh insteps provide breathability, while cushioned foot beds provide all day comfort. The ribbed tops hold the socks in place. They are machine washable for convenience.