18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 6in diameter + Product Details Size -

+ Product Details Size - 18"w X 22"h is the size for the duct opening measurement only

+ Product Details Size – 34"w X 36"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 16 5/8" width X 22 5/8" height

actual front end outer dimensions are approximately 26

actual front end outer dimensions are approximately 32 5/8" width X 24 5/8" height -

18" x 10" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 6in diameter + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 10" OR 10" X 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 9. 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