The SE-SWB A / B Box (yes they could still work on the name...) is designed in such a way that the user can route both 2 inputs to one output as well as 1 input to 2 outputs. So you get 2 guitars without re-plugging on an amp or a guitar on 2 amps. An LED indicates where you are on the signal path. If you do not need it, the battery can be dispensed with. The design is such that you can even switch boxes with it. Convenient and very cost-effective. With higher volumes when switching between the two amplifiers, a low guitar signal can go through the unused amp.