• High quality decoding chip provides excellent sound and low noise • Innovative design, the headphones can be used as common wiredhead phones or TF card headphones • Intelligent controlling, when the audio cable is plugged into the audioinput socket, the headphones will be switched from TF card mode to common headphones mode automatically • Audio output socket for convenient connection with other audio equipment when audio signal is under TF card mode • Volume, previous song, next song and pause control are designed in one knob for easy operation • Built-in rechargeable 3.7V/350mAh lithium ion battery for long playtime • Power on/off switch button requires a certain period of continuous pressing (about 3 seconds )for turning on/off the headphones to avoid unintentional touch on the button and cause wrong on/off operation