Connector: 3.5 mm audio jack<BR><BR><br>Nominal Impedance: 18 Ohm<BR><BR><br>Total harmonic distortion: <0.5% (100Hz .. 10000Hz @ 1mW)<BR><BR><br>Controls (one key):<BR><br>Calling ? answer/reject<BR><br>Listening ? play/pause/forward/back<BR><BR><br>Use with:<BR><br>Smartphone， tablet， laptop， music player or other device with 3.5 mm audio output<BR><BR><br>Speaker type: 9.2 mm dynamic<BR><BR><br>Frequency response: 20Hz ? 20000Hz<BR><BR><br>Microphone: ECM