Wool is a staple of the DeFeet line. We source the highest grade wools on the planet. Combined with DeFeet construction, the result is the finest wool sock that you can buy. The DeFeet wool line is continually growing. This year we"ve added the Classico as well as a SpeeDe. Wool has attributes that can"t be found in other fibers. DeFeet wool socks stay cooler in the heat because of the construction of the mesh. They stay warmer when they are wet and in cooler temperatures because of the amazing thermal properties of wool. Wooleator: Wool is a staple in the DeFeet line of socks. The Wooleator is the wool version of the world famous Aireator sock. Very thin throughout, with the flat-knit StayFast cuff and Aireator mesh weave across the entire top of the foot. The Wooleator is extremely versatile. Use the Wooleator to run, walk, hike, ride bikes, or relax at home.Sizing: S/M (Women 5-8)/35-39.5; M/L (Women 8.5-11.5)/39.5-43.