Detailed Product Description Mono and Stereo 2 in 1 Bluetooth headsets,U&I-20 Main FeaturesDual-Mic & ... -Slim Design, more fashion With In-ear Earpiece, more popular and comfortable BLUETOOTH V2.1, higher version, higher tech. MICRO USB ... , Handsfree, Multi-pointTransmission Power: Class 2Operation Range: Up to 10 MetersFrequency Range: 2.40-2.4835GHzBattery: Built-in Rechargeable 3.7V/75mAh Li ...