1,USB mini speaker for TF and SD card 2,earphone output 3,Built-in rechargeable battery 4,audio input Future:*Support USB, TF and SD card *Stereo sound design, limited space to enjoy unlimited high-fidelity music*Built-in rechargeable lithium battery *3.5MM headphone output interface and earphone interface, wallyson amplifier.*Audio output connection with computer, laptop ect.*Size: 37*68*2184mm, ...