ZM-901  Round 9" Hole Size Brass Grille With Damper; 10" Exterior Diameter

Made to fit into a 9" round hole or duct, these grates have an exterior diameter of approximately 1" greater than their boot size.  The damper is made from finely cast iron, with a Lost Wax Cast brass operator.  None better anywhere, at any price.

This 9" grate is available in either brass or iron ( painted black ZM-IR-901).

You may feel some resistance when opening and closing the cast iron louvers for the damper.  The friction helps to keep the louvers in a set position to your liking, and withstand normal increases in air pressure caused by higher fan speeds from heating and cooling units.