18" x 30" or 30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 12in 75"H – fits a 16"

75"H – fits a 16" X 4" duct opening

Actual Filter Size – 19 3/4"w x 24 3/4" x 1"

actual front end outer dimensions are approximately 12 5/8" width X 12 5/8" height -

+ Product Details Size – 8" x 12" or 12" x 8" is the size for the duct opening measurement only

18" x 30" or 30" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 12in 75"H – fits a 16"+ Product Details Perfect Fit & Easy Sizing Designed for a 18" x 30" OR 30" x 18" duct opening (measured at the opening), with actual outer dimensions of 20. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 17. 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