AVIKA B20 ideal for high quality music while running, jogging, cycling, skating, etc Good noise isolation to create the optimal environment for listening to your favorite tunes, built-in microphone with noise cancellation for clear calling and friends chatting Sweat-proof, lite weight and ergonomic design to enhance your comfort; comes with interchangeable earbuds and ear hooks for secure and personal fit when walking or exercising Built-in rechargeable Lithium battery lasts up to 4.5 hours of talk / play time or 175 hours standby, universally compatible with most Bluetooth-enabled phones. The sound is great and the experience is impressive. When a call comes in, press once to answer. HD voice gives you excellent call quality and background noise is blocked out with effective noise reduction technology. You can use B20 with any smartphone, tablet, laptop or music player.