16" x 30" or 30" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12" Diameter actual front end outer dimensions

actual front end outer dimensions are approximately 36 5/8" width X 18 5/8" height

+ Product Details Size - 18"w X 36"h is the size for the duct opening measurement only

Ideal for Walls & Ceilings: Designed for seamless installation in standard 16" X 16" duct openings

high-impact plastic

16" x 30" or 30" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12" Diameter actual front end outer dimensions+ Product Details Perfect Fit & Easy Sizing Designed for a 16" x 30" OR 30" X 16" duct opening (measured at the opening), with actual outer dimensions of 18. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 15. 75" x 29. 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