The Socks 600 are made from wool terry on the foot and shaft. The merino wool is incredibly soft and does not retain odors even after multiple uses. It can absorb up to 30 percent of its own weight in moisture without feeling damp. These thicker garments are designed as a mid-layer to optimize thermal insulation between the close-fitting functional underwear and the outer layer, which is worn for protection against wind and moisture. They are particularly useful in lower temperatures or during less intense activities. The fabric is a knitted terry, with one side being smooth and the other made of terry loops. The airy terry loops combined with the crimped structure of the wool create a knit that traps a lot of air, resulting in excellent insulation properties.