The hand made WOBO ABY-TM switch, is used for switching between different outputs. The middle switch is used to switch between A and B outputs and the left switch turns on both outputs. The right switch routes the signal to a third socket e.g., for mute tuning or another amp.
The major improvement in a WOBO ABY-TM is the use of relays instead of switches. Most switch based bypass devices use components that are simply NOT DESIGNED for switching audio signals. The relays used in the ABY-TM have been specially designed for switching high-quality audio signals so that there is absolutely no impact on your sound.
The unit also has a ground lift selector switch for getting rid of ground loop problems (common with use of two or more amps) by cutting off the ground on the B output.