I bought my M20 earbuds because I was interested of having an equalizer that would work with all apps and games. At the end it works, but the process is very buggy and painful to do. Using it in a “normal way” which would just work on both sides, only works on one random side every time. So while some music is playing, I have to manually turn them off, then back on only one side to apply any equalizer preset. Turn it off again, then turn back on the other side and re-apply the same equalizer preset. Turn it off, then turn both back on. If one day it is fixed so I could avoid doing all of that, I’ll change it to 5 stars. But for now I don’t think I’ll be getting my hopes up, because I contacted the support about a month ago and never got any sign of reply.