30" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Floor Grille Insulation – A thick blanket

Insulation – A thick blanket of fiberglass insulation provides you with an R-Value of 4

For 6" Round Duct Opening - Spiral or Flex

Elevate comfort while saving on bills with HVAC Premium's Aluminum Adjustable Return Grill

Designed with two mounting base options—solid and ring—it offers flexible installation

Noise free components - no vibrating louvers etc

30" x 8" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Floor Grille Insulation – A thick blanket+ Product Details Perfect Fit & Easy Sizing Designed for a 30" x 8" OR 8" x 30" duct opening (measured at the opening), with actual outer dimensions of 32. 5" W x 10. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 29. 75" x 7. 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