... easy and fast. 3. Hidden microphone Bluetooth headphones,bluetooth headset with microphones Light and comfortableSuper bassWith vol controlCompliant with CE ... indicater8: Adjustable headband9: Working duration:10h,charging duration:2h10: Headset Spec.: frequency response:20-20KHz,SRN:85dB,working Voltage:3 ... 100Hz~10kHz&SRN≥55dB&Sensitivity:-42dB Bluetooth headphones,bluetooth headset with microphones