The volume indicator on my Logitech Z533 speaker volume dial was almost impossible to see so I etched an indicator.
This surface is frequently touched so it should be cleaned first. I used isopropyl alcohol to remove any oils from the surface that might interfere with the etching quality. Soap and water would also work.
Align your dial with where you want the pointer aligned to the front of the machine.
Settings used:
IR 2W
Power (%) 100
Speed (mm/s) 2000
Pass 1
Lines per cm 100
Etch and Enjoy!