3" Circular Round Plastic HVAC Supply Grille Air Diffuser -Vent Duct Cover [Outer Dimensions: 5"] w18h18 + Product Details Size -

+ Product Details Size - 26"w X 20"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 38 5/8" width X 22 5/8" height -

actual front end outer dimensions are 19" Width X 11" Height

this HVAC vent duct cover ensures durability and reliability

Actual Filter Size – 13 3/4"w x 15 3/4" x 1"

3" Circular Round Plastic HVAC Supply Grille Air Diffuser -Vent Duct Cover [Outer Dimensions: 5"] w18h18 + Product Details Size -+ Product Details Size 3" Diameter is the size for the duct opening measurement only, actual front end outer dimensions are 5" 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