Shoemaker AFPB-4X12 4"x12" Aluminum Floor Perimeter Diffuser - Brown 1/8" Bars On 1/3" Centers (See Linear Series) Recessed Screwdriver Operated Opposed Blade Damper To Control Air Volume For Positive Balance Reinforced With Pressure Lock Honeycomb Construction To Withstand Heavy Foot Traffic Satin Anodized Finish