Compact solenoid valves suitable for most gas and fluid handling applications. Where practical, valves are shown with a schematic diagram showing the (circuit) function. The diagram is laid out so that the left-hand side of the diagram describes the valves operation when the coil is energised. When the coil is de-energised, the spring (or servo-assist) return controls the valve and is described on the right-hand side of the diagram. The 3 / 2-way designation indicates a valve with three ports and two modes of operation. It is normal practice to refer to 2 / 2-way valves as two ways. The port designations A, B, P, P1, P2 and R are used on the schematic diagrams and are marked on the valve bodies. Valve bodies are marked for a specific circuit function but can often be used for other functions. Reference to the schematic diagrams and technical specifications indicates the appropriate connections and pressure capabilities when an alternative circuit function is required.