Heat emitters radiate intense infrared heat but emit no light. The perfect 24-hour heat source for your tropical or desert reptile. Ceramic heat emitters can be used to establish an appropriate environmental temperature range for reptiles. This product is designed for use with Repta-Clamp Lamp with Switch. Reptiles are ectotherms or "cold-blooded" animals who depend on he surrounding environmental temperature to regulate their own body temperature. If the environmental temperature in your terrarium is inadequate, your pet may be susceptible to digestive problems or infections. Some reptiles require a night time temperature drop to induce normal breeding behavior. A standard "light timer" available at hardware stores, can be used to turn off the heat emitter in the evening and back on again in the morning to create a more natural environment.