The Enerco Two-Stage Auto-Changeover Regulator provides easy changeover from empty to full cylinder while providing adequate fuel to your RV.• 400, 000 BTU max flow• 2-1/4" inverted female flare inlets x 3/8" female pipe outlet• Propane level indicator located on top of regulator• Includes backflow prevention fittings• CSA certified 2-1/4"" inverted female flare inlets x 3/8"" female pipe outlet Propane level indicator located on top of regulator Includes backflow prevention fittings | Mr. Heater Enerco Propane Auto-Change High-Capacity Two-Stage Regulator