Product Description Material: cotton cloth + carbon fiber Size: (flexible) sole length, 20 cm; sock length: 23 cm; sock 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 Color: gray, black Quantity: 1 pair Package content: 1 pair * heating socks (with battery and charger) 1. Battery Operation & Enlarge the Heating Elements To give your feet a more balanced warmth, our heated socks feature Enlarge the heating elements of the toes and soles of the feet. keep your feet warm all day when they are fully charged. PS: The display of the adapter lights up red during the charging process and green when fully charged. 2. 3 adjustable temperatures Electric foot warmer with 3-stage temperature, the heating range of the electric socks is between 35 C and 55 C. The red LED corresponds to the high temperature setting, the orange LED corresponds to the medium temperature setting and the green LED corresponds to the low temperature setting. 3. Flame retardant safety cotton The heated warm socks are made of cotton, polyester, spandex. The breathable, quick-drying, specially developed, flame-retardant cotton makes you feel more secure during use. It is more important that the far infrared heating elements of the winter socks can stimulate the blood circulation. They are an ideal gift for people with arthritic feet and cold joints. 4. Washable and an average size The heated sock battery support hand wash and machine wash. Note: Please remember to put the charging cable in the socks first before washing. heated socks unisex with average size. One size that fits everyone, super elastic and stretchy for adults, men and women. 5. Widely Used & Best Gift Electric socks are perfect for a variety of indoor or outdoor events such as hunting, hiking, horse riding, fishing, biking, driving, running, camping, skiing, climbing, sleeping, etc. The Ski heated socks could also be an ideal gift for parents, friends, family members and the elderly.