Descriptions: 1 Connect the USB cable to the computer or 5V charger switch interface, coasters begin to generate heat. 2 The need for thermal insulation on the silica glass coasters, then it can play the role of insulation (please don’t use the recessed bottom cup, glass Cup is best) 3 Please do not use this insulation Cup for outside functions. 4 Please Unplug the USB cable when don’t use, to extend the life of the product. 5 It is only used to keep your tea or coffe warm,but not for heating. Notice: 1. Not smooth cup bottom, the insulation cup, the mineral water bottle and the bottom of the thick quilt is not recommended use. 2. Coasters Temperature about 60 degrees， Do not let children play 3. When not in use, cut off the power in time Package included:1 x USB cup warmer， cups are not include. Beverage Warmer for Coffee Cup and Teapot For USB power supply:1. Wipe off the water on the mug. 2. Connect the product to the USB port of the computer or charger. 3. Put the mug on the beverage warmer. 4. The light is on when the product is working normally, and keeps the temperature at 40-60℃ Cautions: During long periods of non-use, pull out the plug or turn off the power switch. The warming effect is different on different materials, it works best with cooper is the best, next with glass, and followed by plastic. And the effect will be improved with a cover on. The center of the warmer is hot when it is working, please don’t touch it. The warmer is to keep the temperature at 40-60℃ only, cannot boil water. Do not wash the product in water. Make sure the output is not less than 2A when using charger as the power supply for the product.Connect to the rear USB port when using desktop computer as the power supply for the product to ensure the warming effect. Do not connect to the front USB port. Do not connect with USB extension cable .Non-professionals are forbidden to take the bottom cover apart.