Rolling Shutter System Steel Octagonal Steel Tube Production Line Rolling Shutter System Steel Octagonal Steel Tube Production Line,Good quality galvanized 60mm 70mm octagonal tube roll forming customized ,has the advantage of high production efficiency and accuracy, easy operation and stable performance.the octagonal steel shaft is on the left or right in shutter box bearing bearing and is the changing female for the roller shutter hangings. Specification No Item Parameter 1