These socks come in 2 sizes:

MEDIUM: Womens 6-9 / Mens 4 1/2 - 8 1/2

LARGE: Womens 9-12 / Mens 8 1/2 - 12

Polypropylene is a performance fiber that quickly moves moisture away from the skin, allowing it to dry rapidly.  Arch support helps to keep the sock in its place during vigorous activity.  Ventilation Channels through the top of the foot allow air to bypass the fabric and help the skin stay dry and comfortable.  Cushioned sole lessens the impact in strike point areas of the foot.

65% Polypropylene, 15% Elastic, 12% Nylon, 8% Sta-Cool®