Lightweight and compact design that folds into 49-key piano. MIDI via Bluetooth capability for direct connection to your mobile device. Dynamic and expressive playing from velocity-sensitive keys. Built-in USB rechargeable battery - up to 8 hours of battery life when fully charged. The built-in stereo speaker system provides instant listening to your playing. A stereo 3.5 mm headphone output allows for "silent" exercise. The piano includes a built-in sound engine with 128 sounds and 128 custom accompaniments that offer a variety of playing style exercises. 30 demo tracks have been specially composed to offer a wide variety of practice accompaniments. Sustain pedal and USB charging cable are included in the package.