These grills do not have a damper. They are used primarily as cover grills for return air or could be attached as a supply grill with no damper. It is a fixed stamped design with 1/2" fin spacing. Keep in mind when measuring, to measure the inside grid, not the outside width. The width will always be larger because of the framing.
672 Return Air Grille
All-steel construction
1/2" spaced fins set at 40 degrees
Exceptional free area
5/16" margin turn back
Bright White finish
Other sizes available upon request
