1.Dual channel AFS frequency automatic search function in dependently. 2 .The frequency can by synchronized between receiver and transmitter via infrared. 3.Four channels which of volume and audio frequency control independently and 4+2 audio frequency output. 4.Transmitter battery monitoring. 5.Handheld, lavalier, headset can be mixed use. 6.LCD display shows status of frequency, AF and RF signal etc. 7.Using four same channel to make the transmitter can exchange. 8.Noise locked, Pilot Tone locked and Squelch Control.