Product Description Material: cotton cloth + carbon fiber Size: (elastic) sole length, 20cm; socks length: 23cm; socks opening: 9 cm battery voltage: 3.7 V battery capacity: 22004500 mAh temperature control: 3 levels adjustable temperature: low end, 35 degrees Celsius; mid-range, 45 degrees Celsius; High-end,55 degrees Celsius Colors: Gray, Black Quantity: 1 pair Package Contents: 1 Pair 100% Heated Socks (with battery and charger) 1. Battery Operated and Enlarged Heating Elements For even more balanced warmth on your feet, our heated socks have enlarged heating elements on the toes and soles. Keep your feet warm all day long when fully charged. PS: The display of the adapter isred when charging, and green when fully charged. 2. 3-level adjustable temperature The electric foot warmer has 3 levels of temperature, and the heating range of the electric socks is from 35C to 55C. The red LED corresponds to the high temperature setting, the orange LED corresponds to the mediumtemperature setting, and the green LED corresponds to the low temperature setting. 3. Flame Retardant Safety Cotton Heated thermal socks are made of cotton, polyester, spandex. Breathable, quick-drying, specially designed flame-retardant cotton gives you confidence during use. What's more, the far infrared heating elements of the wintersocks can promote blood circulation. They make an ideal gift for anyone with arthritic feet and cold joints. 4. Washable and average size heated socks batteries support hand wash and machine wash. Note: Please remember to insert the charging cable into the socks before washing. Unisex heated socks, medium size. One size fits all, super stretchy and stretchyfor adults, men and women. 5. Widely Used and Best Gift Electric socks are perfect for various indoor or outdoor activities, such as hunting, hiking, horseback riding, fishing, cycling, driving, running, camping, skiing, climbing, sleeping, etc. Ski heated socks can also be anideal gift for parents, friends, family members and the elderly.