The Exo Terra Thermostats should be set according to the needs of the animals. Thoroughly research the preferred_x000D_ optimum temperature (POTR) and humidity range for your specific reptile, so you can create the correct temperature_x000D_ gradients and humidity inside the terrarium to allow your reptiles to thermoregulate and maintain their moisture_x000D_ levels. With the Exo Terra Thermostats you can create a well-controlled 24-hour heating/humidifying system that allows_x000D_ you to maintain the required temperature and humidity conditions similar to those found in desert and tropical_x000D_ environments. The Thermostats will also help to prevent overheating and undercooling during hot summer days or_x000D_ cold winter nights.