Dadgummit, now that sock is Darn Tough! Re-engineered to bring you its most tech-savvy snow socks, the new Function X will provide max comfort and warmth. The new tech foot with terry loop cushioning over the top keeps feet warm and comfortable. The cushion is reinforced in the heel for durability, with more terry loops around the shin and calf for a ski sock that fits so well you’ll forget you’re wearing it. All backed by Darn Tough’s lifetime guarantee!