Control knobs are very popular in the electronics and medical device industry. As far as materials go, these knobs are available in glass-fiber reinforced polyamide based techno polymer (which resist solvents, oils, greases, and other chemical agents), steel, stainless steel, and even high quality spun aluminum. They are available with or without pointers, and with or without painted indicator lines.
All Monroe plastic instrument knobs are provided with the set screw for attachment to the shaft. Brass insert is standard on all units for electrical insulating purposes.