The Cotton Ragg Crew uses a Ragg yarn twisting technique that is defined by using one dyed yarn and one undyed yarn to get a knitted finished "marled" appearance. This is a flat knit sock with a flat knit tow seam that sits closer to the foot and can be worn throughout all seasons. 66% Cotton, 32% Nylon, 2% Spandex Made in USA medium = US 6 - 9 large = US 9 - 12