10"W X 8"H [Duct Opening] Aluminum Double Deflection Adjustable Air Supply HVAC Diffuser - [Outer Dimensions: 11.6"W X 9.6"H] 8" Diameter + Product Details Size –

+ Product Details Size – 18"w X 8"h is the size for the duct opening measurement only

+ How To Measure A Round Vent Overall Size:

you can watch this informative video tutorial: How to Measure Your Vent Hole Before Ordering a Grille

+ Product Details Size – 16"w X 8"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 30 5/8" width X 24 5/8" height

10"W X 8"H [Duct Opening] Aluminum Double Deflection Adjustable Air Supply HVAC Diffuser - [Outer Dimensions: 11.6"W X 9.6"H] 8" Diameter + Product Details Size –+ Product Details Size 10"w X 8"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 11. 6" width X 9. 6" height. Design Full Control Vertical Horizontal Air flow Direction. Horizontal blades in the front, Vertical blades in the back, both individually adjustable. High Quality Aluminum The premium durable aluminum will never rust and it will never wear through leaving the material with an elegant,