8"x 8" (Duct Opening Size) 4-Way Stamped Face Steel Ceiling/sidewall Air Supply Register - Vent Cover - Actual Outside Dimension 9.75" X 9.75" The Listed size 12"x6" is

The Listed size 12"x6" is for inside duct opening measurement

18" long heavy duty steel construction with decor oil brushed powder coating finish

and lay-in ceilings

The Listed size 12"x20" is for inside duct opening measurement

The Listed size 14"x24" is for inside duct opening measurement

8"x 8" (Duct Opening Size) 4-Way Stamped Face Steel Ceiling/sidewall Air Supply Register - Vent Cover - Actual Outside Dimension 9.75" X 9.75" The Listed size 12"x6" isThis steel stamp faced register is for sidewall or ceiling applications. The listed size 8"w X 8"h is for duct opening measurement only. Actual outside overall dimensions is 9. 75" wide by 9. 75" high. Difference between "inside" and "outside": Inside (duct opening) is the measurement you can see after taking the vent off the wall or ceiling. "outside" measurement is the surface you can see after the installation. Size selection guide: 1) take the