1.The microphone unit has discussion and auto-tracking of   functions.
2.it using the flocking to process.
3.It has built-in antena and rechargeable lithium battery for each unit and   equip MINI USB charger.
4.The annular blue indicator lamp can show the working state on the   microphone.
5.The chairman unit can set the system working model:FIFO,LIMIT And   FREE.