Boss VB-2 Vibrato
An vibrato pedal used by Prince from 1982 to 2016. It appears on every version of his pedalboard and can be heard on many of his studio recordings. It can be heard on prominently on the Small Club aftershow recording and the drum part to Forever In My Life.
[On So Far, So Pleased] I ran my guitar through a Boss Vibrato and Flanger. The octave and delay effects are from the Zoom 9030.