8" x 28" or 28" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 30.5"] w6h6 Its locking eight-tumbler mechanism and

Its locking eight-tumbler mechanism and supplied key safeguard your thermostat from tampering

+ Product Details Size – 24"w X 12"h is the size for the duct opening measurement only

and centralized air ducted units

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

+ Product Details Size – 24" x 24" with 12" collar T-Bar drop ceiling perforated return grill - metal back casing

8" x 28" or 28" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter - Aluminum - White [Outer Dimensions: 10.5" X 30.5"] w6h6 Its locking eight-tumbler mechanism and+ Product Details Perfect Fit & Easy Sizing Designed for a 8" x 28" or 28" x 8" duct opening (measured at the opening), with actual outer dimensions of 10. 5" W x 30. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 7. 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