This mug warmer is in the shape of a donut, great to go with a cup of coffee or hot tea. Plug N Play USB technology allows this hotpad to work on any computer in any working USB port to keep your beverages hot. Features - Color: Yellow, black, white. - Material: Plastic, electronic components. - Size: About 10.5 * 10.5cm/ 4.13 * 4.13 inch. - Operating Voltage: DC 5.0V. - Operating Current: 1000mA(MAX). - Power: 5W. - Power By: USB Power Cord Cable. - cookie designed for mug warmer, lightweight and portable, easy to tote and take anywhere. - One button operation, just follow simple 3 steps, first connect the USB cord to your computer or any USB port in order to get power resources. Then, place your cold cup on the warmer mat. Finally press the ON button to keep the cup warm and enjoy your hot drinks.