28" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w26h26 Actual Filter Size – 24

Actual Filter Size – 24 3/4"w x 17 3/4" x 1"

With a 8" diameter for the duct opening measurement

actual front end outer dimensions are approximately 36 5/8" width X 28 5/8" height

+ Product Details Size – 16"w X 28"h is the size for the duct opening measurement only

designed for both sidewall and ceiling installations

28" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w26h26 Actual Filter Size – 24+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 12" OR 12" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 75" x 11. 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