Summary

After looking at the several options, I decided to create my own. Experimented with a lot of features, and this one was the best to me. It's for 25mm tube with a safety pin in the end.

Make sure you print it with a lot of bottom layers (I used 14) so it doesn't just snap the top off while in use, and 4 walls, so the main tube is solid from top to bottom. If using PLA like me, make sure you don't leave it at full sun.

It prints without supports... if your printer won't, I suggest lowering the angle a bit in the SCAD file instead of adding supports...