... :4" to 60" stander length:5m or 10m4,Main color: black, orange ect.5,Character: enduring high temparature,acid,alkali,oleic ... working environment such as tunnel,mining, basement, ship building or welding, laboratory , engine room ,the municipal conduit engineering,fire-fighting to ... can conveniently connect to the portable ventilator to use together. black anti-static flexible ventilator ducting