So you love listening to your own music, but don't have an auxiliary port or tape deck in your car? What you need is this Mini FM Transmitter from Monoprice! This FM transmitter can transmit the selected FM frequency to your car's radio in order to play music from your smartphone or MP3 player. Simply select an open radio frequency on the FM transmitter, and tune your radio to the same frequency. Any music played through the transmitter will play through your car's sound system. The transmitter can be tuned to any FM frequency between 88.1 ~ 107.9 MHz at 0.1 MHz intervals. It has a frequency response of 20Hz ~ 16KHz and an effective range of about 5 meters. The FM transmitter's 3.5mm plug can be used to connect to most smartphones and MP3 players' headphone jack. It uses your car's cigarette lighter/auxiliary power socket for power, so you don't have to worry about the battery dying during your favorite song. Features: * Wireless audio transmission over the entire FM frequency range * Works with almost any smartphone or mp3 player * Built-in microphone lets it function as a hands-free communications device * Rechargeable lithium battery * Includes car charging cable adapter with an additional USB charging port 30-day easy returns. No restocking fee. Free lifetime technical support. 1 year warranty.