36" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Copper Coil The integrated eight-tumbler lock system

The integrated eight-tumbler lock system

only measure the "hole" in the wall/duct

Actual Filter Size – 24 3/4"w x 25 3/4" x 1"

+ Product Details Size – 26"w X 34"h is the size for the duct opening measurement only

+ Product Details Size – 32"w X 36"h is the size for the duct opening measurement only

36" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Copper Coil The integrated eight-tumbler lock system+ Product Details Perfect Fit & Easy Sizing Designed for a 36" x 12" OR 12" x 36" duct opening (measured at the opening), with actual outer dimensions of 38. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 35. 75" x 11. 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