Warm your hermit crab's home to just the right temperature with our Zoo Med Hermit Crab Heater. This mini-sized under tank heater is designed to help maintain the proper temperature and humidity levels in small hermit crab enclosures. Undertank heater design gently warms the terrarium glass and substrate, creating gentle warmth for the enclosure. Helps to maintain proper temperatures and humidity levels.4-watt nichrome heating element costs only pennies a day to operate. UL listed for safety. Full one year warranty. Not for wood or metal enclosures.