The 1000 Mile Aproach Walking Sock is a double layered sock that also has merino wool and a high wicking liner to help your feet to maintain a comfortable temperature making these ideal for wearing in the warmer months with lightweight footwear and approach/trail shoes 1000 Mile sportswear are particularly well known for their ingenious double layer socks which feature an inner layer that stays with the foot whilst the outer layer moves with the shoe reducing friction and helping to prevent blisters and reduce wear