... energy 2)strong wind power 3)convenient to move industrail exhaust fanColors:yellow ,red, blue, ect. Size:8" 10 ... novel design,special manufactured for underground cable maintainance,shipping making,exhaust for fire fighting, piping construction and in other violent ... underground cable maintaince,shipping making. 2)blowing bad gas when welding shipbuilding,canning,bridge. 3)exhaust for fire fighting, ...