Technical specification: 1.Working frequency:2.402GHz-2.480GHz. 2.Full duplex communication function.Sending and receving voice simultaneously. 3.Single button for receiving a call/refusing a call/hanging up;power off automatically or manually. 4.Security password system:(Auto password creating) for earphone and adapter couple. 5.Auto 79 channels selection (1MHz per channel).Many people can use it simultaneously in the same place freely. 6.Covering distance:5-10 meters. 7.Battery blow-Light Indicating 8.Talk and standby state-Light indicating 9.Built-in rechargeable Li-battery,supporting 3 hours talking time or 100 working hours. 10.Weight of earphone:11.5g,weight of adapter:8.0g 11.Exterior diameter:30mm