This high-purity stainless steel automatic changeover panel provides continuous, uninterruped gas supply on installations where a reserve cylinder is used. The unit consists of two identical regulators - on delivering gas at a slightly higher pressure than its twin. When the service cylinder is empty, the unit automatically withdraws gas from the reserve cylinder, eliminating the need to shut down the system to replace empty cylidners. The indicating pressure switch gauges denote which cylinder is in use. The high-purity design and components make this system ideally suited for chromatography and laboratory gas applications.