This Zoo Med Repticare Day/Night Timer is a must-have for your reptile habitat if you provide heat at night. This easy-to-program analog timer provides a natural day/night cycle for your pet reptile. The top outlet controls daytime devices, and the bottom outlet controls the nighttime devices. This outlet automatically turns the daytime lights on in the morning and off at night. The bottom outlet controls the nighttime light or heater and automatically turns on at night and off in the morning. The outlets are also grounded for safety.