Come and see our amazing products. Coffee mug warmer use aluminum alloy material, which is esturdy, durable, lightweigh, safe and easy to clean.Coffee mug warmer has built-in smart thermostat control chip, can keep the water temperature around 40-60 75 degrees . Standard USB1.1 4-port HUB connector, supporting full-speed 12Mb/sec and low-speed 1.5Mb/sec rate. On/off one-button control, easy to operate, when the heater starts, there is a red LED light to indicate.In order to improve the thermal conductivity, only flat botttom container is advantageous to the heat preservation. Such as ceramic cups, stainless steel cups, baby bottles and other materials with temperature resistance above 75 degrees. Do not use plastic cups or paper cups. Pls confirm further with us if any query about packing info, inventory status and time schedule.