Nailor Model 0722 Ceiling Dampers are for use in spherical apps, in lieu of hinged door form dampers in any UL/ULC flooring/ceiling or roof/ceiling assembly with up to a three hour fireplace resistance rating wherever air ducts are authorized. Industrial dampers function in industrial and severe duty air apps. The dampers are heavy-duty flanged https://heavydutystainlesssteelda90112.blog4youth.com/37675720/heavy-duty-stainless-steel-damper-manufacturers-no-further-a-mystery