12" x 26" or 26" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Ceiling + Product Details Size –

+ Product Details Size – 16"w X 12"h is the size for the duct opening measurement only

High Quality – Rigid aluminum construction with counter-sunk screw holes (screws included) and no sharp edges

+ Product Details Size – 36"w X 10"h is the size for the duct opening measurement only

+ Product Details Perfect Fit & Easy Sizing - Designed for a 32" x 34" Or 34" x 32" duct opening (measured at the opening)

and Diffusers

12" x 26" or 26" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Ceiling + 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