28" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades with Damper + Product Details Size -

+ Product Details Size - 26"w X 18"h is the size for the duct opening measurement only

+ Product Details Size - 8"w X 36"h is the size for the duct opening measurement only

10"w X 8"h Is The Size For The Duct Opening Measurement Only

Measure the size of the air duct/drywall opening

actual front end outer dimensions are approximately 26 5/8" width X 30 5/8" height

28" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades with Damper + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 16" OR 16" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 18. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 75" x 15. 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