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

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

Filter Size - 31

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

+ Product Spec Sheet Return Air Grille Spec Sheet

Installation Location – Sidewall or ceiling

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