Our shower head never stayed where it should so I decided to try voivoi's shower holder. I exchanged the ball for a pin for our showerhead. I like that you can even exchange the holder without removing the tube.

unfortunately the pin on the first design was a little bit more skew after each shower. So I changed the design and tried ABS instead of PLA. Now the pin broke during the first shower. In the third design I used a screw the reinforce the pin.it was an M4x30. It still holds.

This holder fits on a tube of 18mm. The locker is the same as voivoi's