Designed to be your go-to extra heavyweight boot sock, Trekkers are extremely thick, quite soft, and well built. Created with ultra-soft bison fiber, these socks thick and cushioning. Only properly processed bison fiber is used, 100% free from stuff that will make the socks itchy or abrasive. Trekkers feature a terry loop padded foot bed and are over-plaited in the toe, heel, and slightly up the leg to make sure your feet will be comfortable all day long. Despite the extra cushioning and tough construction, these performance designed socks are intended to be worn with footwear. They are not intended to be worn as house slippers. You certainly can, but wearing them on concrete and abrasive surfaces will impact wear. Base Yarn Composition: 45% American bison down / 50% Merino wool / 5% Nylon, Made in the USA. Sizes from small – extra large.