Quite a simple thing, a 60mm rod with a standard tripod thread on each end. This is to position a camera like the Logitec 920 (which has a tripod thread) in the middle of a ring light that also has a tripod thread.

Creality

Ender 3

Yes

Yes

Slice at an angle of about 30 degrees so that the layers are not aligned with the rod, this works out cleaner than slicing it horizontally. Slicing it standing vertically means the threads will snap off when you turn it.
I used exclusive slicing tolerance and random Z seam alignment.