Works with compatible cup / mug only as effective contact points work in tandem with each other. This intelligent base recognizes metal foreign objects placed accidentally, and stays shut. Panel is waterproof & safe to touch even when switched on. The radio bottom cooling sheet dissipates heat at high temperature & accumulates heat when temperature is low. Mode of heating – wireless induction. Wireless Coaster can be used as a normal Wireless Charger with mobile phones too.