Comfortable fabric: Winter electric thermal underwear set made of soft 95% cotton and 5% spandex for a comfortable and smooth touch, providing warmth without the bulk of heavy coats. Safety performance: Heated underwear features a built-in carbon fiber heating pad for fast heating up to 25-50°C. Powered by a 5.0V power bank, ensuring stable performance and reliability. 3 heating levels: Conveniently located button at the tail of the thermal shirt allows for easy temperature adjustment with a simple press. Heating levels indicated by colors: red for 45-55°C, white for 35-45°C, and blue for 30-35°C. Compatible with most power banks (not included). Machine washable: Simply remove the battery pack and secure the built-in cable. Use a laundry bag for proper care to maintain comfortable warmth for years. Widely used: Designed for reuse in cold weather, ideal for outdoor activities such as skiing, hunting, fishing, cycling, and camping, as well as for individuals working in cold environments.