12" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades with Damper + Product Details Size –

+ Product Details Size – 30"w X 20"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 16 5/8" width X 28 5/8" height

For example

The 1/2" black insulation

Design – Circular return valves - designed to be used in low and medium pressure ventilation air conditioning systems

12" x 24" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Fixed Blades with Damper + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 12" x 24" or 24" x 12" duct opening (measured at the opening), with actual outer dimensions of 14. 5" W x 26. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 11. 75" x 23. 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