The Kenetrek Ultimate Liner sock has the perfect blend of materials for wicking, comfort and durability. Made to be worn as next to skin layer under any of the Kenetrek socks will stay put and provide comfort day in and day out. Made in USA of 77% Polypropylene, 17% Nylon,3% Lycra and 3% Elastic. Over the calf, men's sizes S (wmns 4-7), M (5-8), L (9-12), XL (13-15).