16" x 34" or 34" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12" Round Duct Pipe + Product Details Size –

+ Product Details Size – 18"w X 16"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 30 5/8" width X 18 5/8" height

Actual Filter Size – 25 3/4"w x 9 3/4" x 1"

+ Product Details Outer dimensions: 15

16" x 34" or 34" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 12" Round Duct Pipe + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 16" x 34" OR 34" X 16" duct opening (measured at the opening), with actual outer dimensions of 18. 5" W x 36. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 15. 75" x 33. 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