12" x 4" Adjustable Blade Sidewall Ceiling Register Vent Cover Diffuser Heavy Duty Stamped Steel (Listed Size is for Duct Opening or Inside Measurement)

Adjustable Air Register – Diffuser for sidewall or ceiling applications. The listed size 12“w X 4”h is for duct opening measurement only, Actual outsize overall dimensions is 14“ wide by 6” 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, round ceiling diffusers and adjustable blade sidewall diffusers. Size Selection Guide Measure the size of the air duct opening(the size of the “hole” ). Select the listed size that match the duct opening size. The outside or overall size is 2” larger for both width and length so it can cover the “hole”. Do not use outside measurement for size selection.