Item Type: 37 Key Keyboard PianoBattery: Lithium battery 3.7V 1200mAh (built in)Product Size: Approx. 55 x 11.2 x 3.8cm / 21.7 x 4.4 x 1.5inFunctions: 4 tones, 10 demo songs, volume adjustment, demo song joint singing and electro singing, stop button, volume knob, audio jack, headphone jack, microphone function, single speaker. .wang-edit-text{ font-family:"Arial" important; } .wang-edit-text table { border-top: 1px solid 000; border-left: 1px solid 000; } .wang-edit-text table td, .wang-edit-text table th { border-bottom: 1px solid 000; border-right: 1px solid 000; padding: 3px 5px; } .wang-edit-text table th { text-align: center; } 137 Keys Design: The keyboard is designed with 37 keys, and the portable guitar keyboard can be carried and played at any time. 2With 32 Note Polyphony: 32 notes polyphony is suitable for beginners to practice, allowing continuous notes to sound without being cut off. 3With Lithium Battery: The 37 key keyboard piano has built in lithium battery, you can play directly by pressing the switch. 4Natural Stereo: Advanced wave memory stereo sampling to reproduce natural instrument sounds in stereo. 5Multifunctional Keys: With volume adjustment key, demo song duo, stop button, audio jack, headphone jack, microphone function, single speaker.