Engineered to deliver reliable on-off or throttling operation of automatic control valves, the Fisher® 3025 Size P460-200, P462 and P900 diaphragm actuator can be categorized as either reverse-acting (air-to-open) or direct-acting (air-to-close).

When fluctuating controller or valve positioner pneumatic output signals reach the diaphragm, these spring-opposed actuators react by orienting the valve plug in the valve body.