Solenoid valves are used widely throughout the pneumatics industry, as an effective and reliable method of controlling actuators and similar pneumatically operated devices.

Solenoid valves use electro-magnets to operate valve spools either directly or, more commonly, indirectly, by means of a pilot valve.

Direct operation can only be achieved in valves incorporating almost frictionless, short stroke, steel spools without seals; typically these include directional control valves, which are widely used in America. Although these devices offer relatively fast response times and can be switched at any air pressure, they are relatively large, expensive to manufacture and require additional electronic control equipment before they can function. In Europe, poppet and elastomer sealed spool valves are far more common. These cannot, however, be operated directly, due to their longer stroke and higher levels of internal friction. Instead a small solenoid pilot valve is used to control the flow of air to a pneumatically driven spool.