... whole.StraightslidewaysTYPICALGalvanized steel, light weight, strong rigidity, corrosion-resistantComposed of upper and lowerMain DrivingJiangSuSprocket is made by CNC machining center, which ... bearing, bearing with big capacity,wear resistant, low noise.Upper andlower partsjiangSutop to bottom center adopt to full anti-bias ... safety of passengers,its requirements are surface smooth, tight seam lift