The MO Series declutch-able gear operators offer simple and reliable manual positioning of valves, dampers and other quarter-turn devise when overriding, existing pneumatic or hydraulic rotary actuators. All GLC MO units are suitable for indoor and outdoor use and combine rugged construction, light weight and modular design to provide the most efficient and cost effective solution to a full range of manual override requirements. The self-locking worm gear design means safe and easy operation, positive manual positioning and extremely long life. The GLC override can be adapted to any quarter-turn actuator and may even be installed in the field on existing valves