The Altera Alpaca Prevail Sock is our medium weight performance sock and the perfect choice for the sportsman and sportswoman in all of us. This sock has premium terry loop construction throughout entire sock, reinforced heel and toe and built in arch support. If you are in the most extreme conditions, you will want the Prevail Sock on your feet. Offered in a 9" Crew and 12" OTC. Made here in the USA.