MXR M101 Phase 90 Fx Pedal Rich, warm analog tone. Add shimmery velocity and dramatic swooshing to your tone. The timeless phase shifter used on many classic Van Halen recordings. This device has found its way into many of Eddie Van Halen's recordings, adding a shimmery velocity to lead passages or a more dramatic swoosh to muted strumming. Not just for guitars; it works well with bass, keyboards and even vocals.