Wave Processor / Synthesizer (For GK Pickup)

Fat synth sounds and effects in a compact pedal for GK-equipped guitars
Provides 6 synth-type waves and effects—Saw Lead, Square, Ring Mod, Slow Gear, Sitar and Acoustic
11 chorus and delay effects, plus Color and Level knobs for further tweaking
Rugged, dual-pedal design with simple, knob-based controls

https://www.boss.info/us/products/wp-20g/