Siemens GQD131.1P is a powerful compact electric damper actuator designed for the precision control of HVAC and ventilation systems. It has a spring return system with fail safe performance. Because of its torque capabilities, it can operate dampers in a variety of HVAC applications with efficiency. This actuator is also energy efficient since it operates on a typical 24 VAC/VDC power... https://www.partshnc.com/gqd1311p-siemens-building-technology-24vfloatingdcactuator-20