Product details of Handfree Wireless Bluetooth Headphone Handset Earphones Smart Sport Stereo Features: Ergonomic design headphone, comfortable to wear. In ear design, reducing the world's best low. Unique magnetic control, not easy to fall. Built-in microphone with high sensitivity, clearer voice quality. Built-in lithium battery, support for 2 hours of fast charging, deliver up to five hours of music / conversation resistance. Bluetooth one with two, to meet multisource needs. With a play button, you can control the music player and make and receive calls and other functions.