Nothing special, just the bracket ring for a straight pipe because it looks weird if the pipe is too long without support.

Original Inner diameter is 42.2mm Scale it down for your needs.

I also added a version that should be easier to print at smaller scales.

For example: I want to use a 16mm pipe:

42,2mm = 100% 16mm = x %

x = (16mm*100)/42,2mm = 37,91%

Print at 37,91% Scale.

This thing is of course meant to work with this: https://www.thingiverse.com/thing:1810675