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. Also included are two 12" pigtails to connect the regulator to the propane tank or propane supply.• Allows removal of the empty cylinder for refill without interrupting propane supply• Two 12" pigtails connect the regulator to the propane tank or propane supply• 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 Indicator changes color when tank has been depleted 1/4"" SAE inverted flare inlet / 3/8"" NPT female outlet Includes two 12"" pigtails | Flame King 2-Stage Auto Changeover Propane Gas RV Regulator Kit with Two 12" Pigtails