... 3.width:0.5m-3m 4.shape:Round, Square Galvanized Rectangular Metal Hole Punch Punch Metal /Punched Metal/perforated ... metalMaterialCarbon steel, Aluminum, Brass, Copper.FinishPowder coated,galvanized,polished,or no finishHole shapeRound, Square, Slot, Triangle, Long ... and other noise acoustic noise sources using sound-absorbing panels, can be used for building the ceiling. Dear friend ...