The Mooer Micro ABY MKII is a simple idea well executed to be useful for guitar players. You have one jack (Y) on the left and two jacks (A and B) on the right. In A/B mode the foot switch allows you to toggle between A and B i.e. 1 guitar->Amp A or Amp B. The great thing is that the jacks work in both directions. So you can also do Guitar A or Guitar B -> 1 amp.