Spring return actuator Model EF utilizes rugged components in a pressure cast aluminum housing for added strength and reliability. It offers a high torque output of 270 inch-pounds and a NEMA 4 option to meet tough environmental conditions found in many HVAC applications. The actuator was developed to satisfy high-torque applications with a single actuator. The EF can take the place of two classic AF actuators in a piggyback-mounted application, simplifying wiring and mounting requirements while reducing material and installation costs. The NEMA 4 protection feature allows complete access to change the direction of rotation and allows locking or manually overriding the actuator.