Features : 1. High-quality materials: This heating sock is made of 80% cotton 12% polyester and 8% elastic fiber material. It has water absorption breathability quick drying and elasticity. 2. Suitable for the occasion: focus on the toes to prevent the feet from getting cold which can promote blood circulation. Suitable for arthritis feet and long cold feet and stiff joints giving you a warm winter. 3. Heating parts: The heating parts are in the socks. The specially designed battery bag is safe and easy to carry. 4. Kit includes: one set has a pair of electric socks two 3.7V 2200MAH batteries and two battery chargers (US regulations). The battery takes about 4-6 hours to fill and can be heated for 3-7 hours. 5. Rechargeable heating socks: Rechargeable battery heating socks for cold weather projects or winter outdoor sports winter ski hunting camping bicycles and motorcycles to keep warm. Specification : Material: Cotton Blend Charging time: 4-6 hours Plug Type: USUK Battery: 3.7V 2200MAH Size: about 23x10x5CM / 9.06x3.94x1.97in Weight: about 400 grams Heating time: Red light: about 3 hours Green light: about 4.5 hours Blu-ray: about 7.5 hours includes: 1 pair x heating socks 2x battery 2x battery charger "