Automatic Changeover regulators prevent gas outages by switching supply cylinders over to the reserve cylinder automatically when the primary cylinder is near empty. When the primary cylinder is depleted causing the changeover to occur a red indicator will appear signifying the reserve cylinder in now in use and the primary cylinder can be refilled without loss of service. Features a green indicator which changes to red when the service cylinder needs to be refilled. The new Type I, ACME connection and its ability to shut off the flow in a fire situation is one of those improvements. Meets UL, RVIA and NFPA requirements. Dimensions: 1/4 inch Inv. Flare x 3/8 inch FPT. 225,000 BTU.