12" x 26" or 26" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible with Duct 8" + Product Details Size -

+ Product Details Size - 36"w X 36"h X 2"d (for duct opening measurement only)

actual front end outer dimensions are approximately 36 5/8" width X 22 5/8" height

+ Product Details Size – 16" x 34" or 34" x 16" is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 24" x 28" OR 28" x 24" duct opening (measured at the opening)

actual front end outer dimensions are approximately 23

12" x 26" or 26" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible with Duct 8" + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 26" or 26" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 28. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 25. 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