features advanced BT 4.1 technology, built-in high-grade microphone speaker, hands-free function and lightweight mini design. It will offer you amazing experience and you can greatly enjoy your favorite music when doing sports. Features: Mini and Invisible: Super mini size headphone, invisible and 4g lightweight design is suitable for working, driving, running, climbing and other sports. BT Connection: BT 4.1 Technology ensures transmitting strong signal in high quality and high speed and offering high-fidelity stereo music. Hands-free with Mic: High-sensitivity microphone grasps the detail of voice, ideal for in-car calling or working use, setting your hands free. Simple Operation: With one multifunctional button, easily control playing / pausing, next track, answering / rejecting / ending an incoming-call. Included Charging Box: 40mAh headphone battery ensures about 4 hours of working time. 400mAh charging box enables headset magnetic charging for about 8 times.