From Boss:

Rapid Retuning, Flawless Sound

The XS-1 Poly Shifter delivers instant retuning in a convenient, compact footprint. Driven by advanced BOSS algorithms years in the making, this magical pedal transforms the overall pitch while maintaining your instruments true character. You get speedy tracking, crystal-clear response, and zero compromise in tonewhether shifting down, simulating a capo, or using extreme octave jumps for effect. The versatile XS-1 unlocks a new level of performance freedom, making tuning changes fast, fluid, and seamless.

Features

• Class-leading pitch shifting quality realized with new BOSS algorithms
• Instantly change the pitch of a guitar, bass, or other instrument
• Clear response and natural feel that retains the fundamental sound character
• Change pitch across +/- seven semitones or +/- three octaves
• Balance knob adjusts the mix between the effect and direct sound
• Detune function (+/- 20 cents) to create rich doubling effects
• Selectable pedal switch modes for toggle or momentary operation
• Connect external footswitches for quick access to up to three tuning setups, or use an expression pedal for linear pitch control
• BOSS five-year warranty

Brand new.