This manufacturer-supplied replacement part is designed for use with Heatstar and Mr. Heater compact unit heaters. The circuit board helps to control the unit. It provides an identical replacement for a missing or a faulty component that was installed on a new unit. Please refer to the appropriate diagrams of your model for the exact location and the correct installation of this part. Keep in mind this high-quality circuit board is sold individually. You will need a screwdriver to take apart the housing in order to gain access to the circuit board.