4" Circular Round Plastic HVAC Supply Grille Air Diffuser -Vent Duct Cover [Outer Dimensions: 6"] Powder-Coated + Product Details Size -

+ Product Details Size - 36"w X 18"h X 2"d (for duct opening measurement only)

By simply measuring the width or the length of the vent

Filter Size - 19

+ Product Details Size – 36"w X 10"h is the size for the duct opening measurement only

+ Product Details Size – 30"w X 22"h is the size for the duct opening measurement only

4" Circular Round Plastic HVAC Supply Grille Air Diffuser -Vent Duct Cover [Outer Dimensions: 6"] Powder-Coated + Product Details Size -+ Product Details Size 4" Diameter is the size for the duct opening measurement only, actual front end outer dimensions are 6" diameter. Design Made of strong durable ABS plastic, will last forever & never rust. Easy removal for cleaning. Airflow Improved airflow dynamics long neck bBody reduced noise design integrated spring fasteners. Easy Installation Just pop the diffuser right into the wall duct hole and the side springs will hold it right into