This is my remix of Linear Bearing Greasing Cap by walter to fit on small 12g tube of Super Lube.
It is only for LM8UU (8mm) bearings. You have to cut off the tip of the tube just above the thread like I did (check pictures). I have printed this on MK3 and Zortrax M200 and both prints works fine - could be screwed on without problem.
I suggest to print it on low layer hights <0.15 becase the thread is very small.
Small support is required to hold the center hole (use custom supports in your slicer)