Reptile Systems Ceramic Heat Elements are Perfect for creating necessary warm areas in the terrarium. Supports digestion, promotes well-being and activity. Suitable as a constant heat source in terrariums. Allows night time activity of the animal without disrupting the 24 hour cycle. Ideal in combination with a On/Off or Pulse Proportional thermostat in order to regulate the heat. Only use emitter in the ceramic bulb holder. E27 (Edison Scraw) Fitting.