n a pneumatic system, various pneumatic components like air cylinder, direction control valves, solenoid valves, air operated valves or mechanical valves are connected through flexible tube or hose for flow of compressed air. Sometimes rigid piping is also used in application area like welding, but the use of flexible tube is present in most of the cases in the industry. For normal industrial application, PU (polyurethane) tube or Nylon tube is used. The standard size of the PU tubes are 2.5 mm OD, 4 mm OD, 6 mm OD, 8mm OD, 10 mm OD, 12 mm OD, 14 mm OD and 16 mm OD.