1)saving energy 2)strong wind power 3)convenient to move 4)make low noise and light weight due to die-casting aluminum alloy. 5)with good capacity,the reasonable structure and the strong suction. 6)It's special manufactured for underground cable maintaince,shipping making. 7)blowing bad gas when welding shipbuilding,canning,bridge. 8)exhaust for fire fighting,piping construction and in other violent working situation for ventilation.