1, + PLL technology, make the frequency more stable, the frequency does not change with the environment and produce frequency drift. 2, the frequency can be continuous adjustment within the specified scope. 3, with microphone input interface, and can through digital potentiometer to control the volume of the microphone. 4, audio input by digital potentiometer which can adjust the volume. 5, power can be between 0.1 W and 7 W maximum power continuous adjustment. the power output network for harmonic suppression is very good, make the output spectrum is more clean set the frequency and volume of power lost protection, boot does not need to set up again! Suite main parameters: 1, the input voltage: dc 12 v About 2, input current 3.0 A 2, the audio signal: the maximum input Vpp is less than 1 v. 3, microphone types: cylinder microphone or microphones!!!! 4, working frequency: 76 m - 108 MHZ 5, frequency of 0.1 MHz 6, the distortion degree: 0.03% ~ 0.1% Colour: green Material: plastic + metal Package Contents: 1 x 5W FM stereo PLL FM transmitter 1 x LED screen Note: it's DIY kits, not assembled, need solder yourself The transistor is USE. Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.