12" BUTTERFLY DAMPER - For T-Bar, Drop Ceiling Grilles, (12" round duct opening) Sheet Metal/Adjustable Elbow + Product Details Size -

+ Product Details Size - 14"w X 14"h is the size for the duct opening measurement only

you can watch this informative video tutorial: How to Measure Your Vent Hole Before Ordering a Grille

Ideal for Walls & Ceilings: Designed for seamless installation in standard 18" X 6" duct openings

complies with ASTM E 84

actual front end outer dimensions are 25" Width X 25" Height

12" BUTTERFLY DAMPER - For T-Bar, Drop Ceiling Grilles, (12" round duct opening) Sheet Metal/Adjustable Elbow + Product Details Size -+ Product Details Size 12" round duct opening Heavy Gauge Steel Heavier gauge than needed, built for durability and long life in mind, but still very thin. Installation Location Ceiling. Design This airflow control component are made to connect to a drop ceiling lay in diffuser grille. Powder Coat Finish smooth, shiny, scratch resistant, beautiful. Looks like it was just waxed. + Product Description Introducing the 6" Butterfly Damper Your Solution