Specification Bluetooth Version: V2.1, Chipset: CSR Transmission distance: 10M Frequency Response: 20Hz-20KHZ Talk Time: 12 hours Standby Time: 150 hours Bluetooth Sensitivity:-85dB 7. Build-in speaker mic 8. Speaker: 9. Impedence: 10. LINE-IN Plug .5mm stereo Features 1,Integrated Bluetooth technology with MP3 music, Allow you to convert Music and Phone calling freely 2,Support Bluetooth stereo device entirely to receive A2DP stereo music. 3,LINE-IN available, which can be used to listen music by connecting to PC; 4, Built-in rechargeable lithiumbattery 300mAH. 5,Foldable style, easy to carry; 6,Ultra-soft padding and lightweight adjustable headband provide extreme comfort for long term wear size:77*45*48 weight:0.53