12"w X 8"h [Duct Opening] 3-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 13.75"W X 9.75"H] sidewall expanding or retracting the gap

expanding or retracting the gap to meet your precise needs

High Quality – High quality ABS plastic will never rust

+ Product Details Size - 4"w X 20"h is the size for the duct opening measurement only

the actual front end outer dimensions are 10" in diameter

+ Product Details Size - 20"w X 28"h is the size for the duct opening measurement only

12"w X 8"h [Duct Opening] 3-Way Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 13.75"W X 9.75"H] sidewall expanding or retracting the gap+ 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