This supply air register is designed for duct, ceiling or wall openings that are 16-inches x 6-inches. The front, outside dimensions of the register are 18-inches x 8-inches.Our supply air registers feature:Horizontal blades in the front with vertical blades placed behindBoth sets of blades are individually adjustable and have 2/3-inch spacingOpposed-blade damper with slide operationAluminum roll-formed blades with semi-airfoil designPressure fit nylon pivot points eliminate rattling & looseningAluminum frame with mechanically-locked cornersCountersunk screw holes with painted mounting screwsA sealing gasket to prevent streaks on walls or ceilingDurable white powder-coat finish