This is the selector box. With the Triage you can selectively route one guitar signal on to three different amps per footswitch. A fourth switch (SIDEKICK) makes it possible to activate multiple amplifiers simultaneously. All outputs are transformer isolated, so that no ground loop humming can occur. Each output is equipped with a buffer amp for the volume, meaning the signal can be boosted by up to 12 dB (quadruple the amplification). In addition each output has a phase switch with which you can flip the phase of the signal by 180°. This is a very useful feature since it prevents cancellations that can occur when two amps with different phasing are played simultaneously. Each output also has a ground lift switch.