16" x 24" or 24" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Anodized Aluminum 75"H – fits a 12"

75"H – fits a 12" X 6" duct opening

4" X 12" Is The Size For The Duct Opening (floor/vent hole) Measurement Only

+ Product Description Maximize the efficiency of your ventilation system with our top-of-the-line HVAC grilles and registers

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

16" x 24" or 24" x 16" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Color_Anodized Aluminum 75"H – fits a 12"+ 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