Fender don't make short or medium scale flats so the JMJ mustang comes with long scale Fender flats fitted which sound & feel great to me—in fact I also put a set on my CIJ mustang. If they ever start sounding crappy I have a set of medium scale D'addario Chromes lying in wait—which I believe are Mr Justin MJ's strings of choice, but even after a few years they're still sealed in their packaging. I'd like to try the LaBellas, but I'll probably never get around to it.