16" x 24" or 24" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe but you’ll appreciate the benefits

but you’ll appreciate the benefits over a long period of time

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

angle them down for effective warmth distribution

actual front end outer dimensions are approximately 18 5/8" width X 27 5/8" height

16" x 24" or 24" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter 8" Round Duct Pipe but you’ll appreciate the benefits+ 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