Compatible with stereo/speaker systems, car stereo, headphones which is with 3.5mm audio input. shut down: long press the middle button for three seconds until the red light and blue double flash language change: double click middle button to switch between Chinese and English Bluetooth Version: 5.0; frequency: 2.4GHz; profile: A2DP, speed range: up to 10m/33ft; I/O 3.5mm female, Mini USB female port; Power supply: 5V DC; Charging time: about 30 mins, working time: about 4 hrs Portable Design: Mini size with clip design The portable feature allows you to carry them anywhere you want.support for iPhone, phone Android, other smart phones which with Bluetooth A2DP function. Easy to operate: Connect your speaker/headset with our device, instantly turn your speaker/headset into a speaker/headset Fashionable Bluetooth wireless. Play Wireless: Remove the trouble of wired connection, through the wireless connection and transmission, the user can enjoy music of fidelity anywhere indoors thanks to wireless control.