These are designed for propane tanks or cylinders (which are connected in pairs) in order to ensure a continuous and uninterrupted gas supply, such as in residential heating systems, commercial kitchens, or industrial processes. GR-253H will reduce container pressure to approx. 10-15 PSIG then the second stage complete the process by reducing inlet pressure to 11 inches of water column(0.4 PSIG) outlet pressure. GR-263L is intended for applications such as RV, manufactured home, cabins or other applications with a single appliance or low BTU multiple appliance applications while still permitting maximum range of outlet pressure adjustment. GR-253 series meet UL, RVIA and NFPA requirements.