Allows removal of an empty cylinder for refill without interrupting the propane supply For RVs with dual propane tanks, it automatically switches from the primary tank to the reserve tank when the primary is empty UL LISTED: Inlets are 1/4" SAE inverted flare, and the outlet is 3/8" NPT female pipe thread; rated for 345,200 BTU Double-stage design maintains constant gas pressure under changing demand and conditions; the regulator is factory set at 11" WC (water column); lockout pressure is up to 14.9" WC Compatible with Flame King's 48-inch Thermo Plastic Hose (Model 100383-48) and 12-18 inch INVERTED FLARE Pigtails (Models E12INPT, E15INPT, or E18INPT) For your safety and to ensure leak-free performance, these regulators are assembled using high-strength thread-locker (Loctite) on the adapter connections where the pigtails are attached. This is an intentional safety measure designed to keep critical fittings secure and prevent gas leaks during use. Note: NPT pigtails are not recommended.