14" x 36" or 36" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 6in this air vent diffuser is

this air vent diffuser is built to last

+ Product Details Size - 12" X 12" is the size for the duct opening measurement only

High Quality – High grade steel construction with easy unrestricted air flow for your HVAC system

actual front end outer dimensions are approximately 18 5/8" width X 18 5/8" height

14" x 36" or 36" x 14" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Compatible With Duct 6in this air vent diffuser is+ Product Details Perfect Fit & Easy Sizing Designed for a 14" x 36" OR 36" X 14" duct opening (measured at the opening), with actual outer dimensions of 16. 5" W x 38. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 13. 75" x 35. 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