18" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum with actual front end outer

with actual front end outer dimensions of 5"

actual front end outer dimensions are approximately 24 5/8" width X 20 5/8" height

+ Product Details Perfect Fit & Easy Sizing - Designed for a 8" x 26" or 26" x 8" duct opening (measured at the opening)

actual front end outer dimensions are approximately 41

Ideal for Walls & Ceilings: Designed for seamless installation in standard 12" X 4" duct openings

18" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Aluminum with actual front end outer+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 36" OR 36" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 35. 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