Check the listing for details. 15" x 15" Aluminum Square Ceiling Diffuser, White,18" x 18" Ducting Opening Size. Condition: New. Listed at 52.79 USD. This aluminum air supply diffuser is widely used in malls, office buildings, restaurants, homes, and offices, perfect for ceiling installation for low and medium-pressure intake or exhaust ventilation, air conditioning system, fresh air ventilation system. This vent cover provides horizontal air flow in 4 way for better air distribution.SpecificationExternal Size: 500 x 500mm/19.7 x 19.7 Inch(L*W)Neck Size: 375 x 375mm/14.8 x 14.8 Inch(L*W) for 15 x 15 Inch ventilation duct or canalDuct Opening Size: 450 x 450mm/18 x 18 Inch(L*W)Height: 55mm/0.2 InchColor: WhiteMaterial: Aluminum AlloyPacking List: 1 Pcs x Air Supply DiffuserAdvantageDurable Material: Made from aluminum alloy with a matte finish, this durable air supply diffuser is waterproof, moistureproof, anti-oxidation, and not easy to fade and wear.