Klim Hibernate Sock - Gray/Medium 100% TERRY CONSTRUCTION FOR ADDED WARMTH AND PADDED COMFORT HIGH THERMAL RETENTION VALUE TO HELP HOLD HEAT IN NYLON REINFORCED TOE, HEEL AND SOLE FOR ULTIMATE DURABILITY ARCH SUPPORT STRETCH BAND TO HELP KEEP SOCK IN POSITION PATTERNED BEND TO PREVENT BUNCHING IN ANKLE WHEN BENDING