18"W X 18"H [Duct Opening] 4-Way Aluminum Curved Blade Adjustable Air Supply HVAC Diffuser [Outer Dimensions: 19.75"W X 19.75"H] steel Design – Heavier gauge than

Design – Heavier gauge than needed

Actual Filter Size – 25 3/4"w x 33 3/4" x 1"

9% Pure Copper meeting ASTM B280 standards

All of these grills have dampers

18"W X 18"H [Duct Opening] 4-Way Aluminum Curved Blade Adjustable Air Supply HVAC Diffuser [Outer Dimensions: 19.75"W X 19.75"H] steel Design – Heavier gauge than+ Product Details Size 18"w X 18"h is the size for the duct opening measurement only, actual front end outer dimensions are 19. 75" width X 19. 75" height. Design Individually adjusting curved blades for better air flow control. Screws Included High Quality Aluminum The premium durable aluminum will never rust and it will never wear through leaving the material with an elegant, beautiful, and smooth surface, adds a luxurious touch to any home.