"The Mr. Heater Propane Auto-Changeover 2-Stage Regulator provides easy changeover from an empty to full cylinder while maintaining an adequate fuel flow. This Mr. Heater propane regulator features a convenient propane-level indicator. Operates at 11"" water column with a max flow total of 325,000 BTUs. Both inlets are 1/4"" inverted female flares, with a 3/8"" female pipe outlet. Includes cover bracket and hardware.Manufacturer model #: F273846. Easy changeover from empty to full cylinder while maintaining fuel flow Convenient propane-level indicator Operates at 11"" water column with max flow total of 325,000 BTUs"