The Listed size 12"x 8" is for inside duct opening measurement, actual outside dimension is 13.75" X 10"
All plastic construction with 1/2" fin spacing for high air flow with rust proof feature perfect for areas with high moisture
Three way air deflection design with bright white face and black damper in the back
Multi-shutter damper with easy handle to adjust desired amount of air flow
Two screw holes on each side with distance of 9" and two screws are included