The Manual Override (model GR) is designed to manually move the actuator stem using a handwheel. The internal gear is mounted on ball bearings for high efficiency and for long operating life. All STI actuators may be equipped with a manual override to allow operation of the control element when instrument air is not available and the actuator has to be operated manually. Several sizes are available according to the actuator required. For STI actuators series SCV the gear box is mounted between the actuator and the yoke, for the SC series it is mounted on the actuator stem cap side. The manual override can be used as an adjustable retraction stroke limiter. A specific version can be direct mounted to operate a valve where no actuator is installed.