... stereo audio devices access7. Rechargeable lithium battery8. 3 kinds of power supply method: built-in Li-ion battery, USB from PC, AC ... function won't work when power is from built-in battery).10. Line-in interface: DC3.5 stereo, micro SD, standard ... 5V or adaptor 5V power supply in addition to the battery. Music must stop when voltage is above 5.5V and ...