16" x 24" or 24" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Anodized Aluminum only measure the "hole" in

only measure the "hole" in the wall/duct

+ Product Details Size – 28"w X 18"h is the size for the duct opening measurement only

background-color: #000

Installation – Installs directly on round & oval spiral duct - no frames

+ Product Details Perfect Fit & Easy Sizing - Designed for a 16" x 30" OR 30" X 16" duct opening (measured at the opening)

16" x 24" or 24" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Anodized Aluminum only measure the "hole" in+ 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