Wireless  HiFi  Headphone,  32mm  speaker  driver  delivers  high  performance  sound,  FM  Wireless  transmission  for  freedom  of  movement,  Self-adjusting  inner  headband,  Lightweight  design  improves  comfort  for  prolonged  use,  Choose  from  2  channels  to  minimize  interference,  Sound:  Acoustic  system:  Closed,  Frequency  response:  10  -  20  000  Hz,  Magnet  type:  Neodymium,  Sensitivity:  100  dB,  Speaker  diameter:  32  mm,  Impedance:  24  ohm,  Transmission,  Channel  separation:  >  30  dB,  Pilot  tone  frequency:  19  kHz,  Effective  range:  100  m,  Carrier  frequency  range:  863.0  -  865.0  MHz,  Modulation:  FM,  Number  of  channels:  2,  Battery  charging  indication,  Operating  time:  ~14  hours,  Automatic  power  off,  Accessories:  Audio  cable,  Power  Adapter,  Power  supply  headphone:  2  x  1.5  V  NiMH  R03/AAA,  Power  supply  transmitter:  AC/DC  adapter  8V/200mA,  Product  dimensions  (W  x  H  x  D):  19.5  x  22  x  8.5  cm,  Weight:  0.178  kg