24" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 12in The integrated eight-tumbler lock system

The integrated eight-tumbler lock system

actual front end outer dimensions are approximately 26 5/8" width X 10 5/8" height

Actual Filter Size – 35 3/4"w x 23 3/4" x 1"

actual front end outer dimensions are approximately 27 5/8" width X 12 5/8" height

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

24" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 12in The integrated eight-tumbler lock system+ Product Details Perfect Fit & Easy Sizing Designed for a 24" x 12" OR 12" x 24" duct opening (measured at the opening), with actual outer dimensions of 26. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 23. 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