18" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 10in + Product Details Size –

+ Product Details Size – 14" x 36" or 36" x 14" is the size for the duct opening measurement only

Actual Filter Size – 25 3/4"w x 19 3/4" x 1"

Upgrade your air distribution strategy today – invest in the efficiency and convenience of the 8" Radial Damper

Actual Filter Size – 7 3/4"w x 35 3/4" x 1"

5" - SEE BELOW IN DESCRIPTION HOW TO MEASURE A GRILLE

18" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 10in + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 12" OR 12" X 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 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