The microphone unit has discussion and auto-tracking of functions. It using the flocking to process. It has built-in antena and rechargeable lithium battery for each unit and equip mini usb charger. The annular blue indicator lamp can show the working state on the microphone. The chairman unit can set the system working model:fifo, limit and free. The unit has built-in high fidelty of capacitor sound head , its sound quanlity is clear and low noise. The chairman unit can turn down the delegate unit for anytime by priority button. Its design patent of appearance. Power:dc3.7v-5v Power consumption:â?¦360mw(standby state), â?¦630mw(working) Working temperature:-10â??-40â?? Length of gooseneck:380mm Frequency range:500mhz-950mhz Maximum modulation:60k Radiation power:â?¦+9dbm Frequency deviation: