6" x 28" or 28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 30.5"] RV Mobile Home These are specially sized to

These are specially sized to fit into all drop ceilings

+ Product Details Size - 12"w X 18"h X 2"d (for duct opening measurement only)

Premium Airflow Efficiency - High-performance cube core eggcrate design allows 95% airflow efficiency

+ Product Details Perfect Fit & Easy Sizing - Designed for a 18" x 26" OR 26" x 18" duct opening (measured at the opening)

+ Product Details Perfect Fit & Easy Sizing - Designed for a 12" x 16" or 16" x 12" duct opening (measured at the opening)

6" x 28" or 28" x 6" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 8.5" X 30.5"] RV Mobile Home These are specially sized to+ Product Details Perfect Fit & Easy Sizing Designed for a 6" x 28" or 28" x 6" duct opening (measured at the opening), with actual outer dimensions of 8. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 5. 75" x 27. 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 Made