This product is 738.6MHZ frequency of senior U. You can unscrew the microphone pants into two No. 5 batteries and turn on the switch, the USB receiver is inserted in the USB port of the power amplifier, audio disc machine etc.. At the same time put the 3.5mm plug in the USB receiver, the other plug in the 6.5mm plug in the microphone MIC jack can open the microphone volume switch or reverb can be used. The ideal site wireless distance of about 80-100 meters. This product USB receiver plug in the USB function later if the position for U disk can be inserted into the USB socket words in the USB receiver can also use USB function above.