The Ernie Ball Expression Tremolo delivers foot-sweepable tremolo control, all without taking your hands off the guitar. Choose from 5 distinct waveforms (slow rise, slow fall, sine, square, and harmonic) plus onboard vintage inspired spring reverb to create subtle or dramatic pulsating soundscapes. Control depth, rate, or both parameters simultaneously with the foot treadle. The Expression Tremolos sleek, compact design maximizes playability, while minimizing the footprint on your pedal board. Unlock a virtually limitless tonal palette that simply cant be matched by traditional on/off stompboxes.