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. 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. Men's Chest Sizing: Small 34 36, Medium 37 39, Large 40 42, Extra Large 43 46.