Features: [Bluetooth 4.1 + APT-X] It supports automatic connection after being connected successfully the first time. It has high-fidelity stereo sound quality with APT-X code. It is compatible with almost all the smart phones. [Sound Cavity Structure Design] As an outstanding Bluetooth headset, with the use of fever sound cavity structure design, after experiencing repeated grinding test, it achieves lossless sound quality. [Secure Ear-Hook Design] The earphone includes S/M/L ear tips and special ear-hook design to ensure a comfortable and secure experience for everyone. With the specially designed ear hooks, you will never worry about your earphones falling off in the gym or during a workout again. [Sweat-proof] Built for your active lifestyle, the wire control part is rated IPX4 and the headset part is rated IPX6, so it can withstand dripping sweat. [Ergonomic design] It allows for ultimate wearing comfort to match your active lifestyle like running, jogging, cycling, driving, camping, hiking, gym exercise and other outdoor sports.