For Fire Dampers, Fire & Smoke Dampers and Smoke Dampers, what is important is that all installation recommendations are taken care of (NFPA 90 guidelines, for example).
For Fire Dampers with Fusible Link, insist on UL Certified Fusible Links.
For Dampers with actuators, use a Control Panel, which will permit you to check Damper Operation via the panel (Closing and Opening for Spring Return Actuators).
Finally, source Dampers from a manufacturer who has had his dampers type tested at a competent facility for conformance to UL555 standards.