12" X 8" [Duct Opening] 2-Way Horizontal Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 13.75"W X 9.75"H] 18" Diameter Actual Filter Size – 23

Actual Filter Size – 23 3/4"w x 23 3/4" x 1"

+ Product Details Size – 25"w X 6"h is the size for the duct opening measurement only

+ Product Details Size - 28"w X 16"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 37

no exceptions

12" X 8" [Duct Opening] 2-Way Horizontal Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 13.75"W X 9.75"H] 18" Diameter Actual Filter Size – 23+ Product Details Size 12"w X 8"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 75" width X 9. 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