This aluminum air supply diffuser is widely used for HVAC systems in malls, office buildings, restaurants, homes, and offices, perfect for exterior walls, side walls, ceilings, and floors. Specification Outer Size: 455 x 455mm/17.9 x 17.9 Inch(L*W*H) Inner Size: 395 x 395mm/15.6 x 15.6 Inch(L*W), suitable for the air duct/drywall opening size: 400 x 400mm/16 x 16 Inch(L*W) Height: 45mm/1.8 Inch Color: White Material: Aluminum Alloy Packing List: 1 Pcs x Aluminum Air Supply Diffuser Advantage Durable Material: Constructed from aluminum alloy with a matte finish, this durable and stylish air supply diffuser is waterproof, moistureproof, anti-oxidation, and not easy to fade and wear. Can resist high and low temperatures and anti-corrosion. Adjustable Louvers: Adjustable double-deflection louvers allow you to fully and freely control vertical or horizontal airflow direction to ensure maximum and comfortable airflow. Instruction Measure the wall opening before installing, then drill screw holes on the grille, attach the air supply diffuser to the opening and fix it with screws(not included) Note: Please measure the wall opening and check the product size before purchasing.