OpenAirâ„¢ GND Series Electric Damper Actuator, rotary, spring return, 53 lb-in (6 Nm), 24 Vac/Vdc, 2-position control, 15 sec run time, Fire/Smoke, dual auxiliary switches, bulk pack 10. Designed for UL Listed Smoke Control Dampers and for Combination Fire/Smoke Rated Dampers.