Features *Slim, Light & Compact Design *Walk in, carrying the NP31 with one hand, and play - it's that easy anywhere thanks to the new slim, light and compact design. *Graded Soft Touch Keyboard *76-key Piano-style keyboard.The lower keys are heavy in touch and the higher keys are light, just as on an actual piano, whilst retaining the soft touch of a digital keyboard. *Advanced Wave Memory (AWM) Stereo Sampling *AWM, Advanced Wave Memory Stereo sampling is a sampling system, creating superb wave data that mirrors the sound and expression of the original instrument by using advanced digital technologies. It creates a unique, rich sound by using multiple waveforms. *Built-in Stereo Speaker System *This instrument uses highly efficient amplifiers that pack more sound into a lighter digital piano. With 6 watts per channel, these keyboards are ready to go whenever you are. *Piano Preset songs *It provides performance data for piano songs as well as voice demo songs, for your listening pleasure. *Battery Power or AC adaptor *The NP31 can be used with an AC adaptor, but the 6-hour(with alkaline battery , *Reference data from NP-30 ) battery is the key to Piaggero portability. (Japan Industry Regulation) (Whether and what type of adaptors come with the product vary according to the region in which the product was sold. Please check with your local dealer) *Auto Power Off mode *This is a new, eco-friendly mode. The NP31 comes with a function that turns off the power automatically if the keyboard has not been used for a set amount of time(30 minutes) in order to avoid using power unnecessarily. This supports long battery life. *New ECO energy saving feature *Energy Conservation Optimized means saving energy by powering down after 30 minutes of inactivity *Easy access panel *NP-31 features dedicated buttons for each voice *All new model: NP-11 *61-note, ultra portable version of the NP-31 *10 voices *Change the sound of the instrument by playing electric piano, organ, harpsichord, strings or vibraphone *32-note polyphony *With Yamaha's Dynamic Voice Allocation, 32-notes is all a pianist needs to play and sustain notes naturally. *Lightweight *Extremely lightweight at just under 12-1/2 lbs (NP-31) and 11 lbs. (NP-11) *Operates on 6 AA batteries *No electrical outlet required. Perform Christmas piano music on the north pole without a generator.