The Flame King Auto-Changeover LP Regulator allows you to hook up 2 propane tanks. The regulator automatically switches over to the second tank once the first one runs out and vice versa. The indicator changes color to let you know when a tank has been depleted and needs to be refilled. The inlet is a 1/4" SAE inverted flare and the outlet is a 3/8" NPT female.• Allows removal of the empty cylinder for refill without interrupting propane supply• Double-stage design maintains constant gas pressure under changing demand• For RVs with dual propane tanks• Automatically switches from primary to reserve tank when the primary tank is empty• UL listed regulator• Inlets are 1/4" SAE inverted flare• Outlet is 3/8" NPT female pipe thread Made for RVs with dual propane tanks Inlet is a 1/4"" SAE inverted flare Outlet is a 3/8"" NPT female | Flame King 2-Stage Auto Changeover Propane Gas RV Regulator