Feature: 1. Equipped with two 4000mAh high‑capacity batteries, supports USB charging, and can be used for 4‑8 hours. 2. The built‑in heating elements design fits the feet tightly, making the socks more comfortable to wear. 3. It supports 3‑level temperature control, and the battery can heat the socks to 55°C, suitable for winter use. 4. It can be machine washed or hand washed. Remember to remove the battery before washing. 5. Put charging cord back into battery pocket before washing, and use the laundry bag (included) to prevent the cord from being torn off. Specification: Item Type: Electric Heated Socks Material: Cotton Color: Black Voltage: 5V Current: 2A Power: 10W Temperature Range: 40-55℃ (Low Temperature Range: 40-45℃, Medium Temperature Range: 45-50℃, High Temperature Range: 50-55℃) Battery: 2 x Polymer Li Batteries 8000mAh Weight: Approx. 366g / 12.9oz Size: Approx. 53x10cm / 20.9x3.9in . Package List: 1 Pair x Socks2 x Battery1 x USB Cable Note: 1.Please allow 0‑1 inch error due to manual measurement. Thanks for your understanding.2.Monitors are not calibrated same, item color displayed in photos may be showing slightly different from the real object. Please take the real one as standard.