Heat wave rock mimics a stone heated by the sun (in nature, even after sunset, stones retain some heat for several hours). Various reptiles, including night crawlers, use this type of conductive heat for thermoregulation which is important for metabolism and digestion. Heat Wave Rock automatically turns off when a certain surface temperature is reached to prevent burns or overheating. A fully encased, electronically controlled heating element covers the stone, preventing hot spots. The special thermal conductive resin is waterproof, non-toxic, easy to clean and ensures even heat distribution. These natural-looking Heat Wave Rocks are available in three sizes and are easy to incorporate into any terrarium kit; Wet or dry.