MARSHALL EXCELSIOR Camping LP Gas Fitting, 1in - 20 Female Inlet x 1-5/16in Male ACME/Female POL with Quick Closing Poppet Outlet, Carded. A POL Adapter (Spud and Nut) is required to convey LP gas to the regulator. Excess flow P.O.L. adapters are required for use on RVs. Note: An excess flow valve will not activate if there is a break or leak downstream of the valve that does not equal or exceed the closing flow of the valve or if the excess flow valve installed exceeds the flow capacity of the system.