30" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w8h8 + Product Details Size -

+ Product Details Size - 4"w X 12"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 38 5/8" width X 12 5/8" height -

actual front end outer dimensions are approximately 16 5/8" width X 22 5/8" height

+ Product Spec Sheet Aluminum Return Filter Grille Spec Sheet

+ Product Details Size - 12"w X 14"h is the size for the duct opening measurement only

30" x 36" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w8h8 + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 30" x 36" OR 36" x 30" duct opening (measured at the opening), with actual outer dimensions of 32. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 29. 75" x 35. 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