CAMTOA Rechargeable Auto Heated USB Cup Travel Coffee Tea Mug Cup Warmer Lid Keep your coffee, tea, or other beverage warm. Easy installation and easy operation. With automatic stirring function. Plug and Play, no need to install extra driver. USB powered with built-in rechargeable Li battery, it can get recharged repeatedly. Portable design, you can carry it around during travel. It's also suitable for home and office using.