Roll Up Piano,Digital & Portable 61 Keys Roll Up Piano Electronic MIDI Keyboard with 16 MIDI Output Channels Design Voted as one of "THE MOST AMAZING INVENTIONS" MIDI Keyboard with 16 MIDI Output Channels Design Full Size 61 Standard Keys (C2-C7) 5 Octave Features 100 Background Rhythms,can be connected to an amplifier or headphones Built in 30 demonstration tunes,Built in speaker w/volume control Power Supply AC Power Supply or 4 AA Batteries