ROOT!T's electronic temperature controller is compatible with all heat mats and is an optional accessory for the ROOT!T Heat Mats. The thermostat controls the temperature of heat mats evenly in colder or warmer than normal environments. It provides constant optimum temperatures for specific plants. It has an easy plug-in operation with an illuminated indicator. Features: Easy to use and control Temperature control range 20ºC to 42ºC Controls temperature of heat mats evenly in colder/warmer than normal environments Provides constant optimum temp for specific plants. Easy plug-in operation Indicator light Simple to use 2 YEAR WARRANTY ..