20" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w30h30 + Product Details Size –

+ Product Details Size – 18"w X 18"h is the size for the duct opening measurement only

5" - SEE BELOW IN DESCRIPTION How To Measure A Grille

7/8" Insulated Copper Coil Line - Seamless Pipe Tube for HVAC

+ Product Details Size - The listed 8" diameter refers specifically to the size of the duct opening

+ Product Details Size - 20"w X 18"h is the size for the duct opening measurement only

20" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w30h30 + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 20" x 30" OR 30" x 20" duct opening (measured at the opening), with actual outer dimensions of 22. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 19. 75" x 29. 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