12" x 36" or 36" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Outdoor Vent Covers Actual Filter Size – 23

Actual Filter Size – 23 3/4"w x 33 3/4" x 1"

rust-free aluminum

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+ Product Details Size – 20"w X 22"h is the size for the duct opening measurement only

+ Product Details Size – 20" x 22" or 22" x 20" is the size for the duct opening measurement only

12" x 36" or 36" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Outdoor Vent Covers Actual Filter Size – 23+ 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