DigiTech Whammy DT Owner's Manual page 13

Drop Tune Footswitches
There are two footswitches below the Drop Tune effect section. The DROP TUNE footswitch is
used to turn the Drop Tune effect on and off as indicated by the LED above this footswitch. The
MOMENTARY footswitch is used to momentarily enable or bypass the effect when pressed. This
is designed to create hammer-on and pull-off style effects with chords shifting from a transposed
tuning to normal tuning.
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