Voberry Exquisite USB Powered Portable Coffee/Tea Cup Mug Warmer Beverage Warmers Heater Tray Pad USB powered, no batteries needed. Plug and Play, no need to install extra driver. Perfect for home and office using. Keep your hot coffee, tea, or other beverage warm, temperature range: 40 to 80. Item size: approx. 11X11X2.5cm/4.33"X4.33"X0.98"