I made these to replace the stock potentiometer knobs on my Taranis X9D. The black knurled look matches my black and white theme very well. On top, there is a tiny divot that I filled with white paint to see the orientation. To do this I simply took the tip of a hobby knife and got a drop of paint on the end, then carefully filled in the divot. The old knobs simply slide off and then the inner sleeve needs to be removed and placed in the newly printed knob. Then center the potentiometer and slide on the new knob with the indicator facing up and you are done!
I printed this with the hollow side on the build plate to give the top a nice finish from the print head.