reference standard: QC/T327-1999)
Annotation: The thread of the pole can be left turn, the type of ball joint should add "L", the mark of the thread should add "left", for example XLQJ-6L left, the type will be XLQJW without the seal covering.
1. circle swing agilely
2. the base of ball joint must lubricate fully
3. work on -30°C~°C70)