RS Pro Industrial Solenoid Valves. The RS Pro series of solenoid valves are a range of 2 way valves which are pilot operated. They can be used for liquid or gas and range in size from 3/8 inch to 2 inch. Features and Benefits. Made from forged brass. Pilot operated. Choice of 230 V ac or 24 V dc operation. 2 port, normally open (NO) and normally closed (NC). Liquid or gas use. Full range of sizes from 3/8 in to 2 in. Product Application Information. Ideal for fluid control uses in a wide range of industrial and commercial applications such as;. Autoclaves. Cooling plant and equipment. Watering plant. Fire extinguishing systems. Hygienic and sanitary. Water jet machinery