12" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 14.5"] fixed bar please note that the total

please note that the total outer dimensions of the grille measure 6" in diameter

Filter Size - 23

+ Product Details Size - 36"w X 4"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 16 5/8" width X 32 5/8" height

+ Product Details Size - 12"w X 10"h is the size for the duct opening measurement only

12" x 12" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 14.5" X 14.5"] fixed bar please note that the total+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 14. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 11. 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 Made from