In 1975, RMI produced its only true synthesizer, the $2,995 RMI Harmonic Synthesizer. It is one of the first digital synthesizers to be commercially produced, pre-dating the better-known Yamaha DX7 by almost a decade. It featured 48 keys and two digital harmonic generators, each supporting sixteen different sets, and was equipped with a voltage-controlled filter and octave shifter. Other features included pitch bend, portamento, and controls for amplitude and frequency modulation. Though it was technically advanced, it didn't sell well and was discontinued in 1976.