34" x 20" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Width_20in + Product Details Size –

+ Product Details Size – 18"w X 6"h is the size for the duct opening measurement only

providing a perfect fit for most standard thermostats

+ Product Details Size – 18" Corner Baseboard Grille - White - HVAC corner vent cover

With a 6" diameter for the duct opening measurement

34" x 20" Cube Core Eggcrate Return Air Filter Grille for 1" Filter Width_20in + Product Details Size –+ Product Details Perfect Fit & Easy Sizing Designed for a 34" x 20" Or 20" x 34" duct opening (measured at the opening), with actual outer dimensions of 36. 5" W x 22. 5" H. Please check the measuring guide to ensure a proper fit. Filter Size 33. 75" x 19. 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