Boss SL-20 Slicer Pedal Audio Pattern Processor Instant groove and percussive-melody generator 50 Slice patterns onboard, with adjustable attack and duration, including Harmonic Slice Tap Tempo via onboard pedal switch; internal and MIDI sync Sound characteristics such as attack, duration, effect level, and direct level are controllable via external Expression pedal (sold separately) Variety of output modes, including the unique 3D Panning for spacious sliced FX