Specification: Modulation: FM (turns the tiny screw on receiver with your screw driver to use a different frequency if interference is experienced) Frequency response: 87.5 - 108Hz Output impedance: 600 ohms Controls/parts on transmitter: ON/OFF switch, POWER LED indicator, Volume control, 3.5mm mic jack Controls/parts on: ON/OFF switch, POWER LED indicator, antenna wire, 1/4" (diameter) audio plug Operating voltage: DC 9V for transmitter (battery is included) Operating distance: 30m / 98ft Lapel Mic wire length: 93cm / 3ft Headset Mic wire length: 95cm / 3.1ft Transmitter size: 59.6 x 43.3 x 18mm / 2.3 x 1.7 x 0.7in How to use: 1. Open the bottom cover of the Transmitter, and then insert the battery into the Transmitter with the correct polarity and close the bottom cover until the click ends. 2. Insert the Microphone's connector into the socket of the transmitter 3. Open the battery cover of the, then insert the "AA" battery into the with the correct polarity and close the battery cover 4. Plug the into the input socket for microphone of amplifier, then remove the switches of the Transmitter or to "ON" position, the indicator lamps of the Transmitter and light, it means that the two devices is normal and are ready for working. 5. There is a volume button on the Transmitter and you can adjust the volume by this button. Include: 1*Wireless Transmitter , 1* Headset Microphone 1* Tie Clip Microphone 1* Data Cable , 1* Transmitter Manual