The Mooer Micro ABY allows you to either switch between two source inputs or two destination outputs by stomping on the footswitch. So you could use it to plug two guitars into the same amp but only have the signal from one at a time, or you could use it to switch between two amps while using one guitar! The compact form factor makes it super easy to add this to any pedalboard but please note it's too small for fit a battery in so it needs to be supplied with standard 9v DC power to operate the LED. It will work without power but the LED won't light. New for Mk2 For the Mk2 version of this pedal Mooer have introduced a new A&B mode which means that you are running in to both at the same time. This is great for if you want to run in to two amplifiers at all times and don't need to switch between them.