Boss PS-6 Harmonist pedal, produced dec 2010 making it one of the early production runs.
It builds on the legacy of the PS-5 pedals, being a bit more distinct in terms of effect modes and less experimental.

The effects are unique, but needs a bit of dialing in together with a basic understanding of keys in usage. Thus not for everyone, unless you stick to the DETUNE mode, which is a bit chorus like but very distinct.
A very recommendable addition to any board and will reward your efforts.

This pedal is in great condition and comes with original box, instruction and even promotion materials from Boss (sticker and programme 2011).

PS-6 includes 4 effect modes

Major/Minor Pitch Shifter (Harmony Mode): Generates vocal-style harmonies automatically based on the scale key you select.

Pitch Shifter: Creates fixed-interval pitch shifts (up to ±2 octaves) regardless of key signature—great for doubling, octave effects, or unconventional interval shifts.

Detune: Adds a slightly pitch-shifted, micro-detune copy of your signal alongside your dry signal. This produces a rich, lush, analog-style chorus/doubling effect without the modulation sweep of a standard chorus pedal.

Super Bend: Allows extreme pitch bending via expression pedal or by pressing and holding the footswitch—shifting pitch up to -3 to +4 octaves for wild "whammy" effects, dive-bombs, or rapid pitch rises.