20" X 6" [Duct Opening] 2-Way Horizontal Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 21.75"W X 7.75"H] Adjustable Return + Product Details Size -

+ Product Details Size - 30"w X 28"h is the size for the duct opening measurement only

Operating from -40°F to +248°F

By means of the smooth surface

Width vs Height

Actual Filter Size – 31 3/4"w x 25 3/4" x 1"

20" X 6" [Duct Opening] 2-Way Horizontal Fixed Curved Blade Air Supply Diffuser Register Vent Cover Grille [Outer Dimensions: 21.75"W X 7.75"H] Adjustable Return + Product Details Size -+ Product Details Size 20"w X 6"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 21. 75" width X 7. 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