Although it is a special purpose, it is used for the head part of the 3D printer. Since the head moves back and forth and right and left, when it is a normal fitting, a twist is applied to the tube, which may result in encountering an accident such as lock pin breakage or tube detachment failure. By exchanging with this rotary joint, the load on the tube was reduced, the movement of the modeling head became smooth, and as a result the load on the head drive motor was also reduced. The difficulty is that the rotary thrust up and down about 0.8 mm, so the tube thrusts together. It is perfect if you lose the thrust of this part.