Heatwave Rock The Exo Terra Reptile Heatwave Rock Electronic Heat Stone simulates a stone heated by the sun. Various reptiles, including nocturnal, use this form of conductive heat for thermoregulation which is important for metabolism and digestion. The Exo Terra Reptile Heatwave Rock Electronic Heat Stone automatically shuts off when a certain surface temperature is reached to prevent burns or overheating. The fully-encased electronically controlled heating element covers the stone to prevent hot spots. Measures 12 x 7 inches.