1.Lightweight and compact lithium-ion battery is rechargeable via USB cable<br />2.Ergonomic shape， adaptable to ears<br />3.Remain stable even if body is in motion<br />4.Smooth structure and soft silicone rubber insert that give max. comfort even when worn for long time.<br />5.Control music playback and calls easily.<br /><br />size: about 140 x 120 x 20mm (width is adjustable) <br />Functions: Bluetooth audio play; answer， hang up， reject calls; <br />I. Key <br />1 multifunctional key (middle): switch function (long press for about 5 seconds until the red and blue lights flash alternately and quickly starting up into pairing mode; long press for about 3 seconds to switch off); play and pause function (short press to pause in playing music); calls function (incoming call， short press to answer; end of the call， short press to hang up; incoming call， long press for about two seconds， hear ding sound， reject call) <br />2 previous/next song & volume keys (left and right): short press to volume +/-; long press to previous/next song <br />II. Interfaces: Mini USB， MIC <br />III. Device parameters <br />1 Working power supply: DC 5V Mini USB <br />2 Bluetooth version: V3.0 + EDR <br />3 Working distance: about 10 meters (without interference environment) <br />4 Charging time: about 2 hours <br />IV Bluetooth connection instructions Make sure your device supports Bluetooth function， long press switch button for about 5 seconds until the red and blue lights flash alternately and quickly into pairing mode， search and connect on your device， after successfully connected， blue indicator light of the earphone flashes once in 5 seconds interval <br /><br /><img src="http://img6.eachbuyer.com/x9/p100/bi616_2.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p100/bi616_3.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p100/bi616_4.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p100/bi616_6.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p100/bi616_7.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p100/bi616_8.jpg" />                                                        <img src="http://img6.eachbuyer.com/x9/p100/bi616_9.jpg" />