Excela-Flo™ Standard Compact 2 Stage Regulator (MEGR-291P) by Marshal Excelsior. 1/4" FNPT Inlet x 3/8" FNPT Outlet. Packaged option consists of a plastic clamshell with barcode. With Drip Lip Vent. The MEC MEGR-291 Series two-stage regulators are approved for use in nearly all portable applications and outdoor cooking appliances utilizing low pressure. They feature all zinc body construction, high and low 1/8" NPT pressure tap ports, an integral second stage drip lip vent and optional standard or 90 degree vent locations.