8" X 4" [Duct Opening] 2-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 9.75"H X 5.75"H] w16h16 Equipped with a lever to

Equipped with a lever to adjust airflow to your preference

Ideal for Walls & Ceilings: Designed for seamless installation in standard 12" X 6" duct openings

Actual Filter Size – 27 3/4"w x 17 3/4" x 1"

but still very thin

order a 14x20

8" X 4" [Duct Opening] 2-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 9.75"H X 5.75"H] w16h16 Equipped with a lever to+ Product Details Size 8"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 9. 75" width X 5. 75" height. High Quality High quality steel with counter sunk screw holes (screws included) and no sharp edges. Equipped with a lever for easy airflow adjustment and dampening. Airflow Control Adjustable airflow lever allows precise control over the direction and volume of air. Installation Location