Extra warm: Thick and warm socks which create heat from your body. Material: Made of cotton and polypropylene. The outer layer is pure cotton and the inner layer features thermostatic aluminium threads to reflect heat. Features: Extremely comfy, soft, lightweight and breathable. Winter socks: Ideal to keep your feet warm and dry in winter - use daily, for hiking, winter sports and more! Self-heating socks: Get one, three or five pairs of self-heating socks. Sizes: Adults UK shoe sizes 5-7 or 8-12. thick Self-Heating Socks | Living Social | Living Social