Descriptions: Cable Length about: 100CM  1*  This cup pad Round diameter is 9cm,The actual working part is 3.5cm x 3cm, The temperature of the heated portion of the surface of the coaster is maintained about 50-80 degrees when it working (except the thermometer, no other things are placed on the cup pad , then get this measurement results). 2*  Material:Silicon, Electronic component: 3.5cm x 3cm 3*  Connect the USB cable to the computer or 5V charger switch interface, coasters begin to generate heat.  4*  Please Unplug the USB cable when don't use, to extend the life of the product. 5*  Heating effect is not obvious; recommended for keep hot water Warm,  it will help tea or coffe slower to cool ( 200ml hot water long time keep Warm about 35-40 degrees) 6*  Warm effect: Adapter > Power Bank > Computer 7*  Thin glass flat bottom cup and metal flat bottom cup for better heating Notice:  1. Please don't use the recessed bottom cup, Thin glass flat bottom Cup is best 2. When the cup pad is working, Do not let children Touch 3. When not in use, cut off the power in time   Package included 1 x USB cup warmer, cups are not include Send without Retail Package