16"W X 16"H [Duct Opening] 4-Way Aluminum Curved Blade Adjustable Air Supply HVAC Diffuser [Outer Dimensions: 17.75"W X 17.75"H] Aluminum Adjustable Curved Blade Filter Size - 9

Filter Size - 9

actual front end outer dimensions are approximately 30 5/8" width X 22 5/8" height

The process is intuitive: simply select the appropriate ceiling square for your grill

The permanently attached eight-tumbler lock with a supplied key adds an extra layer of security

+ Product Details Size – 28"w X 28"h is the size for the duct opening measurement only

16"W X 16"H [Duct Opening] 4-Way Aluminum Curved Blade Adjustable Air Supply HVAC Diffuser [Outer Dimensions: 17.75"W X 17.75"H] Aluminum Adjustable Curved Blade Filter Size - 9+ Product Details Size 16"w X 16"h is the size for the duct opening measurement only, actual front end outer dimensions are 17. 75" width X 17. 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.