The Moog Music MF Ring is an analog ring modulator that is based on the best selling Ring Mod in the world, the Moogerfooger MF-102. Its unique tone voicing circuit adds a new musical dimension to ring modification, making it easy dial in everything from octaves and choral dissonance to harmonic undertones and synthesized lead lines. The expression pedal input provides hands-free control of the Freq control for sound sweeps, pitch shifting effects, and playing between two scales on the fly. Unlike other ring modulation pedals, the MF Ring can also be battery powered.Moog Music