The Maxi-Heat MH500iQ is designed to provide heat in harsh conditions with two independently operating heater units providing up to a combined 1,000,000 BTUs of heat. The IQ system automatically calibrates each heater unit so you don't have to change nozzles or test and retest with a smoke spot tester. The iQ system continuously monitors the heater, producing a higher degree with less soot and smoke. This heater is a top choice for worry-free jobsites.