1. This headphones are a doubles of functions headphones, headphones all receive and dispatch with a machine the function, can use on the computer the lead-in chats the QQ MSN Skype etc. Function(Take lead-in microphone headphones) 2. Effectively there is not any position that limit in the range of receiving. 3. The radiowave can pierce through the wall, the floor, the glass waits for objects 4. Adopt 2.4G high frequency(UHF) and convey the three-dimensional acoustical signal distance is direct 60 m. 5. Under the same transmission frequency, can be a lot of is received. 6. The transmitter has no signal automatic shut-down function while inputting signals 7. Can use various kinds of sound sources, like TV, CD/DVD, Computer, etc. 8. Using the frequency synthetic technology of newest phase locking cycle( PLL) it is steadier to work 9. Shoot the machine to will shut down automatically in had no signal input 1.8-3 minutes Specification: PLL function Frequency: 2400-2500MHz Frequenz: 15Hz ~ 22KHz Distortion: <0.1% S/N Ration: 95 dB SENSITIVITY: -83dBm Effective transmitting range: Up to 100 feet Headphones battery: 700mA/H rechargeable battery AC Adapter with UL-listed Deliver the way: Is to adopt 1: 1 deliver Packing: CARTON BOX: 427*327*452.4mm QTY: 6PCS N. W.: 6.3 KG G. W.: 7.1 KG