14" x 18" or 18" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe High Quality – Commercial grade

High Quality – Commercial grade aluminum - will never rust - designed for warehouses

actual front end outer dimensions are 13" Width X 13" Height

+ Product Details Size – 30"w X 28"h is the size for the duct opening measurement only

our Circular Air Supply Valves are ideal for low and medium pressure ventilation air conditioning systems

actual front end outer dimensions are approximately 36 5/8" width X 30 5/8" height

14" x 18" or 18" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe High Quality – Commercial grade+ Product Details Perfect Fit & Easy Sizing Designed for a 14" x 18" OR 18" X 14" duct opening (measured at the opening), with actual outer dimensions of 16. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 13. 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