Asian Walnut Acacia Unfinished Flush Mount Wood Floor Vent Register 4 x 12 This flush mount vent is for 3/4" floors Overall Vent Size: 14 1/2" x 6 3/4" x 3/4" Duct Opening Size: 12" x 4" Wide louver spacing to ensure ample air flow Removable vent inset for easy cleaning