As the "original air-flow design sock", the Aireator is the sock that kicked off the air-flow rage years ago. Today, the Aireator still leads in durability, wicking, drying, and air permeability. Aireator stays cooler and more comfortable on your feet and lasts longer than anything else out there. That is why Aireator remains the top pick of atheletes competing at the highest levels of sport. Sizing: Small (Women 6-8); Medium (Men 7-9 / Women 8.5-10.5); Large (Men 9.5-11.5 / Women 11-13); Extra-Large (Men 12+).