26" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 18" Diameter + Product Details Size -

+ Product Details Size - 4"w X 22"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 20 5/8" width X 18 5/8" height

Actual Filter Size – 23 3/4"w x 11 3/4" x 1"

this diffuser is the perfect blend of function and style for your home

26" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 18" Diameter + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 26" x 30" OR 30" x 26" duct opening (measured at the opening), with actual outer dimensions of 28. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 25. 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