GENTEC® PD3400 Series Specialty Gas Control Panel is a Semi-Automatic Changeover System which provides for continuous gas supply without interrupting the system during cylinder changeout. When the primary bank is nearly depleted, a changeover will occur. The reserve bank will then begin to supply gas to the alternate cylinder. The inlet valve on each bank provides the user additional safety while replacing the cylinder(s) on the empty bank before the next changeover occurs. The HP vent valves may be used to purge the lines of any residual contamination. The line regulator executes a second stage pressure reduction, providing a consistent outlet pressure and flow. Available in both Brass and Stainless Steel.