6" X 6" [Duct Opening] 1-Way Air Vent Adjustable Aluminum Curved Blades Integral Multi-Shutter Damper HVAC Diffuser [Outer Dimensions: 7.75"W X 7.75"H] w6h6 + Product Details Size - CL 34 12B 35 Product Details Size 6 Extruded Aluminum Ceiling

+ Product Details Size - 18"w X 30"h is the size for the duct opening measurement only

+ Product Details Size - 12"w X 24"h is the size for the duct opening measurement only

+ Product Details Size - 12"w X 34"h is the size for the duct opening measurement only

actual front end outer dimensions are approximately 10 5/8" width X 30 5/8" height

+ Product Spec Sheet Corner Baseboard Grille Spec Sheet

6" X 6" [Duct Opening] 1 Way Air Vent Adjustable Aluminum Curved Blades Integral Multi Shutter Damper HVAC Diffuser [Outer Dimensions: 7.75"W X 7.75"H] w6h6 + Product Details Size CL 34 12B 35 Product Details Size 6 Extruded Aluminum Ceiling + Product Details Size 18"w X 30"h is the size for the duct opening measurement only + Product Details Size 12"w X 24"h is the size for the duct opening measurement only