Castelli Free 9 Sock - Men's;

The Castelli Free 9 Sock is to regular socks as space shuttles are to balsa-wood gliders--the basic design is similar, but everything that matters is totally different. The Free 9 is woven from Meryl Skinlife fibers, which are engineered to be antimicrobial, highly breathable, and moisture wicking, so your feet stay fresh, dry, and comfortable. A high-density woven band under the arch supports your foot and prevents slippage without adding any extra thickness, a flat toe seam prevents irritation, and an open mesh panel at the cuff increases airflow to provide unbeatable ventilation.