Type: Wireless Headset
Speaker: 40mm;
Impedance: 32ohm;
Frequency Modulation (FM):
FM A: Right channel: 2.8MHZ left channel: 2.3MHZ;
FM B: Right channel: 3.8MHZ left channel: 3.2MHZ;
Striking Distance: About 50M;
Power Supply: 2 AAA batteries;
Battery Life: 48hours

Notes:
1) Apply to wireless and wire;
2) Transmit distance can be 50M;
3) Receivers can be used simultaneously;
4) Headphone will switch automatically to silence when there's no signal;
5) Audio has a built-in microphone, which enable chat on the internet.