Full  duplex,  noise  and  echo  cancellation,  DSP  technology               
Frequency  Range:  2.4GHz  spectrum
Bluetooth  specification:  2.0
Working  Distance  Range:  10  Meters(class2)
Built-in  microphone  and  loudspeaker.
Voice  dial  &  Redial&TTS.
USB  PORT:  for  firmware  upgrade  only  
Pairing:  Memorize  up  to  8  mobile  phones  simultaneously.
Charging  Time:  Within  2  hours
Talking  Time:  Up  to  10  hours
Standby  Time:  Up  to  150  hours
Rechargeable  Battery:  Lithium-ion,  3.7V,  640mAh  installed
Battery  Protection:  Over  charge  and  over  discharge  protection
Input  Current:  350  mA  (internal  controlled)
Input  Voltage:  DC  5V
Speaker  Power:  2W  (max)
Speaker  Impedance:  4  ohm
Sensitivity  of  Microphone:  -58dB±2dB