This pedal is the secret weapon on my board. I actually got mine customized so that it worked A_A / B_B with one switch, because I run a guitar through it, through the loop and to my amp OR my violin, through the loop and to an active DI. Mine has three buttons: Tuner (which tunes whichever instrument I've got selected); loop (which is always on) and the button to switch between my violin and my guitar. Super simple, bulletproof pedal and it's lasted me almost 4 years at this point. Best $100 piece of gear I've ever owned.