JAM Pedals RetroVibe Mk.4 Chorus + Vibrato Effect Pedal JAM Pedals RetroVibe Mk.4 Chorus & Vibrato Effect Pedal | No Limit Guitar Co, Idaho Falls The JAM Pedals RetroVibe Mk.4 is a ground-up all-analog Uni-Vibe-style chorus and vibrato pedal widely regarded as one of the finest interpretations of the... MSRP: Was: Now: $469.00 Add to Cart