34" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 18in diameter Actual Filter Size – 13

Actual Filter Size – 13 3/4"w x 31 3/4" x 1"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 30" x 24" OR 24" x 30" duct opening (measured at the opening)

provides a modern look and quiet operation due to its half-inch by half-inch cube design

40"w X 16"h Is The Size For The Duct Opening Measurement Only

+ Product Details Size - 5" Diameter is the size for the duct opening measurement only

34" x 18" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 18in diameter Actual Filter Size – 13+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 18" Or 18" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 20. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 75" x 17. 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