two replaceable batteriesLong battery life up to 6 - 8hours of calling 200 hours standby time 2-3 hours charging time. work long time continuously.</br>comfortable to useErgonomically-shaped in-ear plugs and lightweight brings comfortable and relaxed feeling even after long-time wearing.</br>Unique Siri Functioncan use freely voice control without hands through IOS Siri-enabled devices after successfully pairing.so you can free your hands from your phone.</br>High Fidelity SoundBluetooth headset is equipped with CSR chip and APTX. In-ear design isolates noise effectively. echo cancelling and background noise cancelling.</br>Integrated Multi-point Technologyintegrated multi-point technology lets you connect two devices at once so you can seamlessly switch between your business and personal phones.and won't miss any calls !</br></br>Product Description</br></br><b>Question&Answer</b> <br> <br><b> Q:Why is the volume very small? </b> <br>A:You can adjust the volume on the headset as well the phone if you use Android phone. <br><b>Q: How to deal with when you can't hear the other's sound duing the call? </b> <br>A: You need to change 'speaker mode' to 'UFO'?? if you use the phone to answer the call. <br> <b>Key Features: </b> <br> [SIRI Function] provide responsive interaction with Siri. Free your hands from your phone. <br> <br> [Bluetooth CSR4.0 Technology]provide more stable Bluetooth signal . <br> <br> [Two line]One headset pair with two Bluetooth-enabled devices at the same time. so you can answer calls with two devices or listen to music one on