16" x 18" or 18" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades Some of the best features

Some of the best features aren't readily apparent

actual front end outer dimensions are approximately 20 5/8" width X 32 5/8" height -

actual front end outer dimensions are approximately 34 5/8" width X 18 5/8" height

+ Product Spec Sheet Aluminum Return Grille Spec Sheet

actual front end outer dimensions are approximately 18 5/8" width X 28 5/8" height

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