The Semi-Automatic Panel is available as an individual item. It consists of two high pressure regulators and a line pressure regulator, all with pressure gauges. The inlets are fitted with non-return valves and isolation valves (with OPEN and CLOSE windows) as required by the standard. A lever on the right hand regulator indicates the supply side and requires to be re-set on each changeover. Accessories such as safety relief valve / Flashback arrestor units and out of gas alarm systems can be added.