1、Connecting Sound: This onboard microphone can also be connected to external sound, adjust the volume potentiometer can change the volume, adjust the inductor can change the frequency between 88 to 108MHZ either frequency point. 2、Large Range: The circuit adopts the base frequency signal plus frequency doubling amplification plus final high frequency amplification total of three levels, open space transmitter distance is better than 100m/328ft. 3、Anti Interference: FM transmitter board kit, using frequency doubling circuit to make the frequency more stable, reduce the human body induction brought about by the frequency drift of the trouble. 4、Multi Application: FM transmitter module kit, a wide range of applications, suitable for electronic information engineering, high frequency electronic circuit experiments and testing with. 5、Signal Frequency: DIY radio experiment board kit, adjust the inductor can make the base frequency signal in 44 to 54MHZ, use the nonlinear transistor to produce double frequency signal 88 to 108MHZ. Item Type: FM Transmitter Board Kit Material: PCB Adoption: Base Frequency Signal Plus Frequency Doubling Amplification Plus Final Stage High Frequency Amplification Application: Electronic Information Engineering, High Frequency Electronic Circuit Experiments and Test Battery Specification: 2 x AA Batteries (Not Included) 1 x FM Transmitter Board 1 x Charging Board 1 x Sound Cable 1 x User Manual