The Ramsey FM30B USB Car FM Transmitter is built with the through-holetechnology and comes as a do-it-yourself kit. It features PLL synthesizerfor a drift-free operation and is designed around RF tight vinylclad metal enclosure for interference-free sound reproduction. Viewand change the setup mode, 256 steps of audio volume and RF outputpower with the help of the LCD display and front panel. All the updatedsettings are stored in a non-volatile memory for ready access anytime." The LCD display of this MP3 car FM transmitter also shows ""Quality"" of Signal"" for you to make changes and get optimum sound quality."The line level audio inputs consist of standard RCA connectors andpower inputs feature EMI filters and a PCB inductor for an alignment-freeoperation. This device effectively equalizes the left and right audiolevel variations using a separate balance setting for superior output.Drawing power from a 15 VDC supply, it operates in the range of 13.8to 16 VDC. The front panel LED of this wireless FM transmitter turnsgreen to indicate that the device is transmitting.