The Cavagna Two Stage Automatic Changeover Regulator ensures continuous gas flow, automatically changing from the exhausted service cylinder to the full reserve cylinder. Full-empty indicator changes color from green to red to alert you when it's time for refilling. Overpressure protection device reduces the amount of gas released into the air. Excess flow safety devise automatically shuts off gas in the event of a leak. Includes protective cover and mounting bracket. Inlets: (2) 1/4" inverted flare, Outlet: 3/8" FPT, 160,000 BTUs/hr. (1) Change Over Regulator and Hardware.