18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 14in diameter with actual outer dimensions of

with actual outer dimensions of 22

+ Product Details Size – 24"w X 30"h is the size for the duct opening measurement only

actual front end outer dimensions are 25" Width X 13" Height

+ Product Details Size - 36"w X 20"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 10 5/8" width X 26 5/8" height

18" x 20" or 20" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 14in diameter with actual outer dimensions of+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 20" OR 20" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 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