The 3H37266-3 conversion kit adapts your Hot Dawg heater from natural gas to propane gas so you can use your Modine heaters in areas where the is no natural gas supply. It must only be used with the Modine HD125A heater. The conversion kit must be fitted by a licensed gas/appliance technician. For all your HVAC replacement parts we offer fast shipping options to get your parts right to your door when you need them most and our USA based customer service team are standing by to assist you with your buying questions.