16" x 24" or 24" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe + Product Details Size -

+ Product Details Size - 20"w X 6"h is the size for the duct opening measurement only

+ Product Details Size - 14"w X 18"h is the size for the duct opening measurement only

Operating from -40°F to +248°F

angle them down for effective warmth distribution

+ Product Details Size - 8"w X 4"h is the size for the duct opening measurement only

16" x 24" or 24" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe + Product Details Size -+ Product Details Perfect Fit & Easy Sizing Designed for a 16" x 24" OR 24" X 16" duct opening (measured at the opening), with actual outer dimensions of 18. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 15. 75" x 21. 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