Features:  [Ergonomic Design] Small size and light weight, compact and portable to use and carry in your pocket.  [Built-in 500mAh Lithium Battery] Wireless use for convenience, rechargeable through USB cable, 180 days long standby.  [Multifunctional Instrument] With built-in 13 kinds of instruments including piano, accordion, violin, cello, saxophone, clarinet, flute, trumpet, horn, tuba, guitar, bass and jazz drum, you can achieve solo, duet and quartet with your friends at will.  [Various Exercises] Including scale exercises (a range of three octaves from bass to treble), rhythm exercises (144 rhythms) and repertoire exercises ( having 10 repertoires). After the exercise, the system will realize intelligent evaluation, satisfying music lovers of different levels and realizing zero-based enjoyment of music.  [Challenge Mode] Press and hold for 2 seconds to enter the challenge mode. Two devices can be connected to achieve interactive challenges, and the system will intelligently determine whether to win or lose.  [New Intelligent Evaluation Technology] Realize autonomous learning and effect evaluation, improving the enthusiasm of autonomous learning.  [Innovative Integration of Play & Health] It can exercise fingers, relieve pressure, coordinate brain, develop intelligence and effectively prevent aging diseases, which can be a right-hand man for reshaping interpersonal and family entertainment.    Specifications:  Model: MD01  Material: ABS  Color: Red / Blue (Optional)  Power Supply: 1 * 3.7V 500mAh lithium polymer battery  Rated Voltage: DC 5V  Charging Method: USB charging  Item Size: Approx. 63*63*96mm / 2.48*2.48*3.78in  Item Weight: Approx. 110g / 3.88oz  Package Size: Approx. 12.2*9*7.8cm / 4.8*3.54*3.07in  Package Weight: Approx. 250g / 8.82oz    Note:  Please do not place the product under water, in wet or high temperature places, otherwise it may cause failure.    Packing List:  1 * Hand Piano  1 * USB Cable  1 * User Manual (English)