12" x 36" or 36" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w18h18 Actual Filter Size – 33

Actual Filter Size – 33 3/4"w x 15 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 6" x 22" or 22" x 6" duct opening (measured at the opening)

+ Product Details Size – 12"w X 6"h is the size for the duct opening measurement only

+ Product Details Size – 6" x 12" or 12" x 6" is the size for the duct opening measurement only

Crafted meticulously from high-quality steel

12" x 36" or 36" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w18h18 Actual Filter Size – 33+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 36" or 36" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 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