Empire SRB-18T Automatic Blower for the SR-18T, BF-10, BF-20 Vent-Free Gas Heaters. The Empire SRB-18T Automatic Blower increases the effectiveness of your Empire Vent-Free Gas Heater SR-18T, BR-10, or BF-20 (whether it's wall-mounted or on a floor stand) while working automatically in conjunction with the thermostat. Empire's state-of-the-art centralized blower design quietly circulates the warm air. It fits both the Natural Gas and the Liquid Propane models.