If you’re looking for a quality A/B with a Tuner out, this is it! The design is super quiet, reliable and made to handle a lifetime of use.The A/B/T lets you A/B two amps, pedal boards, or anything you can imagine. You can also flip it and use the input as the output and the outputs as two inputs. It has a dual color (red/green) LED for A & B and a white LED for the Tuner Mute switch.Label: B = B Output A = A Output T = Tuner Output I = Input