1.product specifications a. keyboard: 49 (61)standard keys b. tone: 100 tones are available (00~99 tone control) c. rhythm: 100 accompaniments available (00~99 rhythm accompaniment) d. digital display: in which the tones and rhythms of the roller piano are displayed. e. inner connection of amplifier: earphone/amplifier(home theater) can be connected externally. f. power supply: with power saving design. inbuilt 4 aa batteries (can be played continuously for 5 hours), available for outer connection of power. 2.features new generation (roll up piano), is designed in mini and compact size, that is portable, simply roll it up and put inside the storage bag, you can bring it everywhere. its ready for playing after unfolded, it can connect externally home theater, and stereo, brings more joys and happiness during family parties and gatherings. 100 tones and rhythms are available for product, including piano, saxophone, harp, guitar are available for selection. it's not only for professional players, but good for beginners as well, connect it with earphone, one can play it silently, with numerous functions and settings such as recording and demonstrative songs, which serves as supplementary tools during practice.