16" x 20" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille accordion-header { display: flex

accordion-header { display: flex

By simply measuring the width or the length of the vent

+ Product Details Size - 26"w X 4"h is the size for the duct opening measurement only

+ Product Details Size - 22"w X 26"h is the size for the duct opening measurement only

16" x 20" Cube Core Eggcrate Return Air Filter Grille for 1" Filter return grille accordion-header { display: flex+ Product Details Perfect Fit & Easy Sizing Designed for a 16" x 20" OR 20" X 16" duct opening (measured at the opening), with actual outer dimensions of 18. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 15. 75" x 19. 75" x 1" Premium Airflow Efficiency High performance cube core eggcrate design allows 95% airflow efficiency, reducing energy costs and maximizing HVAC system lifespan. Durable, Rust Free Aluminum