The Zoo Med Hermit Crab Heater HC-30 is designed to help maintain proper temperature and humidity levels in small hermit crab enclosures. This mini-sized heating pad features a 4-watt nichrome heating element that operates efficiently, costing only pennies a day. It is UL listed for safety and easy to install, making it a reliable choice for keeping your hermit crabs comfortable. Ideal for small glass terrariums.