Thermal sock that provides maximum warmth and total comfort. 7 times warmer than the average cotton sock. Features a unique manufacturing process together with Heat Holders innovative Japanese designed thermal yarn. Ensures that maximum warmth is held close to the skin, keeping feet warmer for a longer period of time. Includes a gentle grip for all day comfort. Non-binding and diabetic-friendly, provides relief for cold feet due to circulation problems. TOG (Thermal Overall Grade) rating 2.3.