Boss PS-5 Owner's Manual page 34

FLUTTER
Hawaiian
Simulated quick up and down movement
on tremolo bar (Simulated cricket)
34
PEDAL PITCH SHIFTER
Pedal pitch shifter for great riff chords
and other sounds
* Connect the Roland EV-5 (optional) to the EXP jack.
Pedal pitch shifter - perfect for solos,
leads, and other riffs and licks
* Connect the Roland EV-5 (optional) to the EXP jack.