For use with two cylinders. UL Listed body is assembled and leak tested with two 300PSI leak test gauges, wall mounting brackets, and 3/8” FPT Outlet. Connect 2 pigtail hoses to regulator inlets and to cylinders. This 2 stage regulates cylinder pressure more efficiently to stove, and has 75% more BTU capacity (at service cylinder) than the 1 stage regulator. With both cylinder valves open it automatically changes over to full cylinder when 1st selected cylinder is empty. Indicator dome shows orange until selector switch is pushed fully towards full cylinder. Then empty tank can be disconnected for refill. Meets ABYC Marine Standard.