Hermit Crabs need a habitat that replicates their natural environment as closely as possible. The Black Nighttime Bulb provides the heat that the Hermit Crab would normally receive in the tropics at night. simulates natural moonlight Use Flukers Thermometer and Hygrometer inside your crabs enclosure to make sure your crabs enviroment is the correct temperature and humidity. br/>Sold in Quantity of: 1