A thermostat is not rated for tank, cage, or tub size. A thermostat regulates the heat source. Without proper regulation, temperatures can swing wildly and that is never good!

Check out the thermostat FAQ section on the Reptile Basics site here: http://www.reptilebasics.com/Thermostat-FAQ-sp-10.html. These are the thermostats that Reptile Basics sells: http://www.reptilebasics.com/Thermostats-p-1-c-250.html and also . Rich at Reptile Basics is a terrific guy and is very available to answer further questions after reading the FAQ.

These t'stats are also top notch: http://www.spyderrobotics.com/products/index.html. Dion is also terrific to deal with and is available for questions.