Yamaha REFACE DX Portable FM Synthesizer 4-operator FM Sound Engine offers dynamic and expressive additive synthesis 32 Voice memory locations allow storing and recalling favorite Voices Integrated phrase Looper: capture song ideas or just jam! HQ mini keyboard (37-keys) allows fast, natural performance with premium feel and response Built-in speaker system lets you play any place, any time.Type of Keys-Mini synth keys with initial touch.