... steel,Blade:aluminum alloy 2,Large air volume,low noise,high-speed,light weight 3,With CE certificate Size:8" 10"12 ... in other violent working situation for ventilator. with good insulation, high pressure and large air volume character. Portable ventilator connect with ... can be used at tunnel, basement, ship building or welding, laboratory ,warehouse to ventilate waste air,harmful gas,dust ect.