Main Features:  Dual magnetic stereo to restore high-quality sound.  Portable roll-up design for easy use and carrying.  Thick silicone keys, rebound feedback design, real touch; the keyboard is equipped with an independent touch sensing area, and the pronunciation is clear and precise.  Bluetooth connection APP -  It can connect to the mobile phone Bluetooth. Support music original accompaniment to play the connection, you can also achieve online teaching through software, zero-based can also complete the self-study. Support microphone input function to achieve self-singing.  Can be used as a percussion -  Built-in 140 sounds, 128 rhythm demonstrations, to meet the function of playing more instruments and different styles of music, while pointing out the keyboard drum function, to achieve the drum on the keyboard.  Large energy, let the music keep running -  2000mAh battery capacity, USB charging / power supply; sustainable performance for 15 - 20 hours under full power.     Specifications:  Sound: 140 kinds;  Rhythm: 128 kinds;  Demo songs: 80;  USB output: MIDI input / output;  Battery capacity: 2000mAh ( including );  Time: 15 - 20 hours ( fully charged );  Charging time: 4 hours;  Rated voltage: 5V;  Bluetooth: BT4.0;  88 key: 138 x 22 x 2cm;  61 key: 100 x 22 x 2cm.     General:  Model Number: Vvave;  Type-K: Roll Up Drum;  Materials: Resin;  Structure: Other;  Key Number: 61,88.     Dimensions and Weight:  Product weight: 0.7000 kg;  Package weight: 0.8000 kg;  Product size (L x W x H): 100.00 x 22.00 x 2.00 cm / 39.37 x 8.66 x 0.79 inches;  Package size (L x W x H): 40.00 x 24.00 x 5.00 cm / 15.75 x 9.45 x 1.97 inches.     Package Contents:  1 x Hand Roll Electronic Piano;  1 x Data Cable;  1 x Sustain Pedal;  1 x Manual.     Note:  In order to make customers understand the function of the product, the picture below will translate the keys of the piano into English, but the keys of the actual product are in Chinese.