28" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12in diameter Actual Filter Size – 23

Actual Filter Size – 23 3/4"w x 17 3/4" x 1"

+ Product Details Size – 12"w X 34"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 32" x 24" OR 24" x 32" duct opening (measured at the opening)

With a 6" diameter for the duct opening measurement

+ Product Details Perfect Fit & Easy Sizing - Designed for a 30" x 32" OR 32" x 30" duct opening (measured at the opening)

28" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12in diameter Actual Filter Size – 23+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 24" OR 24" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 75" x 23. 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