TC Electronic provides two new harmoniser stomp boxes: one for the guitar player, and one for the keyboardist. Both generates two additional vocal line real-time - the guitar version analyses the strings that sounds, and the keyboardist's solution receives a MIDI file which instructs the box what to generate from the input. Both boxes contain a small reverb and delay, too. Harmony-G, the guitarist's box is here, and Harmony-M, the other one is here.