10"w X 8"h [Duct Opening] 1-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 11.75"W X 9.75"H] 10in diameter + Product Details Perfect Fit

+ Product Details Perfect Fit & Easy Sizing - Designed for a 20" x 25" OR 25" x 20" duct opening (measured at the opening)

+ Product Details Size – 36"w X 20"h is the size for the duct opening measurement only

+ Product Details Size - 36"w X 16"h is the size for the duct opening measurement only

+ Product Details Size - 16"w X 14"h is the size for the duct opening measurement only

10"w X 8"h [Duct Opening] 1-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 11.75"W X 9.75"H] 10in diameter + Product Details Perfect Fit+ Product Details Size 10"w X 8"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 11. 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