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.<br> .wang-edit-text{<br> font-family:'Arial'<br> important;<br> }<br> .wang-edit-text table {<br> border-top: 1px solid<br> 000;<br> border-left: 1px solid<br> 000;<br> }<br> .wang-edit-text table td,<br> .wang-edit-text table th {<br> border-bottom: 1px solid<br> 000;<br> border-right: 1px solid<br> 000;<br> padding: 3px 5px;<br> }<br> .wang-edit-text table th {<br> text-align: center;<br> } 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.