10" X 4" [Duct Opening] 3-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 11.75"W X 5.75"H] Color_R-4.2 Yellow + Product Details Size -

+ Product Details Size - 18"w X 28"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 10 5/8" width X 10 5/8" height

Actual Filter Size – 31 3/4"w x 23 3/4" x 1"

Designed with a ring base for flexible installation

+ Product Details Size - 10"w X 10"h X 2"d (for duct opening measurement only)

10" X 4" [Duct Opening] 3-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 11.75"W X 5.75"H] Color_R-4.2 Yellow + Product Details Size -+ Product Details Size 10"w X 4"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 11. 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