28" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w14h14 3 * Insulation density is

3 * Insulation density is 30kgs/CBM = 0

+ Product Details Size - 8"w X 24"h is the size for the duct opening measurement only

from 4" to 20"

+ Product Details Perfect Fit & Easy Sizing - Designed for a 22" x 24" OR 24" x 22" duct opening (measured at the opening)

28" x 30" Cube Core Eggcrate Return Air Filter Grille for 1" Filter w14h14 3 * Insulation density is+ Product Details Perfect Fit & Easy Sizing Designed for a 28" x 30" OR 30" x 28" duct opening (measured at the opening), with actual outer dimensions of 30. 5" W x 32. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 27. 75" x 29. 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