BWireless binaural music Bluetooth headsetWeight: 100 g / full setBluetooth version: V4.2Play music / talk time: about 3-4hoursStandby time: about 100 hoursBattery type: rechargeable polymer lithium batteryFunction: fast charging, HD callVoice: full EnglishThe Bluetooth earphones has 90min talk time or music playtime, with up to 100 hours standby time.Enjoy hands-free talk time and music listening experiences with this true wireless earphones, say goodbye to tangled wires.Works with Bluetooth 4.2 technology to provide you stable connection, ensuring you clear sound quality while making or receiving phone calls. Charge before using! (The connecting process has been introduced in the manual with details, please read it before using the earphones)Battery lasts 50 mins each time.If no sound in one earphone, sync the earphones as described in the manual:1. Set up two earphones in the status of red and blue lights interval flashing both , and then click twice in one earphone. 2. If the light of one earphone turns dark, then the matching process is complete.3. Now searching earphones devices in the smart phone to complete the connection process.(The connecting process has been introduced in the guildance book with details, please read it before using the earphones)