The Xtreme Heater was the first heater to be tested for the ignition protection requirements of the ABYC E11, the U.S. Coast Guard, ISO 8846 and SAE J1171. True forced air heating circulates air more effectively, heats more evenly for more accurate climate control. Automatic thermostat turns heater on at 40F and off at 55F +/-3 the tightest tolerance on any bilge heater on the market.