RV, Double Stage, Propane, Auto Changeover Regulator, Replacement For 5' Hose In Propane Kit #59123, Excess Flow Soft Nose P.O.L. x 1/4" Inverted Male Flare, Connects A Propane Cylinder To Any Device That Has A 1/4" Inverted Female Flare Connection, Comes With Dual Propane Tank Hookup, It Has Automatic Changeover Regulator That Maintains The Constant Gas Pressure & Automatically Changes From Empty Tank To Full One, Regulator Allows The Removal Of Empty Cylinder For Refill Without Interrupting Propane Supply.