18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Return Grille actual front end outer dimensions

actual front end outer dimensions are approximately 16 5/8" width X 30 5/8" height

Actual Front End Outer Dimensions Are 16" Width X 5" Height - SEE IN DESCRIPTION HOW TO MEASURE A GRILLE

+ Product Details Size – 24" x 36" or 36" x 24" is the size for the duct opening measurement only

+ Product Description Upgrade your HVAC system with our 5" Round Air Vent Supply Grille

18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Return Grille actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 16" OR 16" X 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 18. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 75" x 15. 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