HBW 12"x 8" (Duct Opening Size) 3-Way Stamped Face Steel Ceiling/sidewall Air Supply Register - Vent Cover - Actual Outside Dimension 13.75" X 9.75"

HBW Stamp Faced register for sidewall or ceiling applications. The listed size 12"w X 8"h is for duct opening measurement only, Actual outside overall dimensions is 13.75" wide by 9.75" high. Difference Between grilles, registers, diffusers and vents： Grille – a series of deflectors in the shape of blades or fins fixed in a frame to allow air to pass through from duct to room space Register – a grille attached with a damper or valve to control the air flow volume Diffuser – a unit with duct connecting piece and a larger face piece with multiple blades to spread out air flow to multiple directions. Examples are drop ceiling T-bar diffusers and round ceiling diffusers. Size Selection Guide Measure the size of the air duct opening(the inside of duct “hole” ). Select the listed size that match the duct opening size (inside). The outside or overall size is 1.75” larger for both width and length so it can cover the “hole”. Do not use outside measurement for size selection.