The "BTU" is a propeller type unit heater that combines the latest tubular heat exchanger and inshot burner technology with the quality and reliability you have come to know with Beacon/Morris. STANDARD FEATURES: 20 gauge tubular heat exchangers 9 sizes ranging from 100 to 400 MBH Inshot type burner Direct spark ignition system 20 gauge jacket panels with baked enamel finish Power vented Easy access control panel Certified for category I and III venting Terminal strip low voltage wiring 82% thermal efficiency 10 year warranty Factory fire tested