36" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Grilles actual front end outer dimensions

actual front end outer dimensions are approximately 36 5/8" width X 34 5/8" height

+ Product Details Outer dimensions: 15

Strong aluminum frame & cube core that never rusts

+ Product Details Size – 18"w X 12"h is the size for the duct opening measurement only

Installation Location – Sidewall or ceiling

36" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Grilles actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 36" x 24" OR 24" x 36" duct opening (measured at the opening), with actual outer dimensions of 38. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 35. 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