Unfortunately my 386dx40 pc case is missing a turbo button/reset/lock panel. I would like to make a replacement.

I think the easiest to make will be just a turbo button with a led underneath that lits when pressed. For this to look good I would like to put a black slightly translucent plastic in front(like one in front of led 7 segment displays). Unfortunately I don't know which plastick is it(the name of it).

Some vendors sell "black pmma", but I'm not sure if this has some light transmissivity sufficient to see a led through it. If anyone knows what kind of plastic is it, please let me know.