The Tonebone Twinline is a unique device that enables a guitarist to share effects pedals between two amps when using the amplifier's built-in (rear-panel) effects loops. Consider the problem: Many guitarists prefer to use the effects loop in the amplifier to insert pedals into their signal chain. This is particularly useful with delay pedals where applying echo to the signal after the guitar amp's preamp distortion results in more distinctive notes and more pleasing sonic results. A problem arises when using two amps on stage: how do you toggle the pedalboard between the two amps? The guitar player must either duplicate his pedal setup (one for each amp) or completely change his setup by connecting the pedals to an AB switcher and then connect the pedals to the front panel inputs of the amps.