American Water Heaters BFG61-50T40-3PV Propane Residential Water Heater, 50 Gallon Non-CFC Polyurethane Foam to prevent heat loss and reduce energy costs Piezo Electric Igniter for easy start-up Fused Ceramic Shield Tank for anti-corrosion protection Factory Installed Side Temperature and Pressure Valve Combination Thermostat/Energy Cut-Off