GMX120-3 | Belimo | Damper ActuatorGMX120 3 Damper Actuator, On Off, floating, 24 to 240VAC non spring return For on off and floating point control of dampers in HVAC systems. Actuator sizing should be done in accordance with the damper manufacturers specifications. The actuator is mounted directly to a damper shaft up to 1. 05 in diameter by means of its universal clamp. A crank arm and several mounting brackets are available for applications where the actuator cannot be direct