12"W X 6"H [Duct Opening] Never Rust Plastic 3-Way-Vertical Air Supply Register - HVAC Vent Duct Grille - Off White [Outer Dimensions: 13.75"W X 7.75"H] RG66 Black-HP Think of the diameter as

Think of the diameter as a straight line from one end to the other

actual front end outer dimensions are approximately 27 5/8" width X 30 5/8" height

To Maximize Ventilation Results

+ Product Details Size – 10"w X 16"h is the size for the duct opening measurement only

+ Product Details Size - 30"w X 30"h X 2"d (for duct opening measurement only)

12"W X 6"H [Duct Opening] Never Rust Plastic 3-Way-Vertical Air Supply Register - HVAC Vent Duct Grille - Off White [Outer Dimensions: 13.75"W X 7.75"H] RG66 Black-HP Think of the diameter as+ Product Details Size 12"w X 6"h is the size for the duct opening measurement only, actual front end outer dimensions are approximately 13. 75" width X 7. 75" height. Design Rigid gauge ABS plastic. Rigid gauge built for durability and long life in mind, but still light and handy. Powder coat finish. Smooth, scratch resistant, beautiful. Looks like new after years of use. Screws Included High Quality High quality ABS plastic will never rust, no sharp