Which gauges of wire should be appropriate for IEMs like Shure or Etymotic? I apologise if this is a "dear God, not again" question. I'm on mobile and maybe it's Android Chrome's fault, but I can't get the search function to give me an input thingy, and in the wiki section on wiring it...

I have a pair of earphones that I intended to replace the plug on, however, I'm a little confused by the wires.  They have an inline remote/mic.   When I stripped off the outer sheath, I found Copper, Red and Blue, as expected, but inside the Green-stripped wire, I found another very fine...