Description1. High quality sound,and comfortable to wear.2.Using version 2.1 + EDR Bluetooth technique,it would be more convenient on the pairing process.3.The bulit-in lithium battery usage time is 8 hours,standby time is 100 hours. Product CharacteristicCarrier Frequency 2.4G Receiving Range 10M 360°FM Mode GFSKTransmitted power 4dBm frequency response 20Hz~20KHzSNR >78dBDistortion <0.1%working voltage 3.3~4.2VDriver Diameter ?30mmDriver Impedance 32? Mic Dimensions ?6.0×1.8mmMic Impedance ?2.2K?frequency response 50Hz~5KHzheadphone approx.71.2g