The Yamaha MU90R is a professional-grade sound module designed for use in live performance and studio recording. It is a multi-timbral, 16-voice polyphonic synthesizer with a wide range of sounds and effects. It has been used by many professional musicians, including the likes of Herbie Hancock, John Mayer, and Steve Vai. The MU90R features a powerful sound engine with a wide range of sounds and effects, including a variety of acoustic and electric instruments, drums, and percussion. It also has a built-in sequencer and arpeggiator, as well as a variety of modulation and effects options. Additionally, it has a USB port for connecting to a computer and a MIDI interface for connecting to other MIDI devices.