We've found this to be an easy-to-use On/Off temperature control system for your reptile terrarium's heating and cooling devices, plus it has a temperature probe and alarm functionality to bring attention to extreme temps.

Overall, this is a convenient and reliable thermostat for your vivarium and has an easy-to-read LCD screen. 

• On/off thermostat
• Controls up to 600W of heating devices and 150W cooling devices.
• Includes one socket / plug for one heating or cooling device.
• Works with under tank heaters (UTHs), ceramic heat emitters, and low wattage devices.
• The remote sensor comes with 6 feet (185cm) of cable.
• Easy to change between heat and cool.
• LCD display
• Convenient two-button programming.
• Controls temperatures between 50ºF and 122ºF (10ºC to 50ºC).
• Built-in memory in the event of power failure.
• Alarm flashes and sounds when temperatures reach extreme high or low levels.

Note: Not for use with mercury vapor or fluorescent bulbs. 

About ON/OFF Thermostats:

Simple on/off thermostats will simply turn off the heating device when the temperature you’ve set is exceeded, and then it will turn the heater back on when the temperature has dropped below your set temperature. 

On/off thermostats are popular because they’re usually more cost-friendly, however, they can cause more significant temperature swings in your animal’s enclosure due to completely shutting off the heat source. This also causes stress to the heat lamp filament, often reducing the bulb’s lifespan drastically in the process. As such, on/off thermostats should only be used with low-wattage or low-output heating or cooling devices like heat mats (under tank heaters / UTHs), heat tape, ceramic heat emitters, and cooling fan systems.