Hayward Series PCD and PCS Actuators are the best choice for applications requiring pneumatically-actuated true union ball valves, three way ball valves or butterfly valves. These actuators are available in models with appropriate torque outputs for all valves from 1/4" all the way up to 24" pipeline size.The Series PCD actuators are air-to-air (double-acting) actuators, while the PCS Series are air-to-spring (fail safe) actuators. Air-to-air actuators require air pressure for both actuation cycles, open and closed. Airto- spring actuators utilize mechanical springs to operate one of the actuation cycles. This type of actuator can be set to have the spring, rather than air pressure, either open or close the valve.