Plug and Play: 1. Plug the FM transmitter into the cigarette lighter outlet, it will turn on automatically and show the battery voltage of the car. 2. Turn your car radio to an unused FM frequency, then match this FM transmitter to the same fm station. FM channels 87.5 MHz - 108.0 MHz, 0.1MHz/step. 3. Insert a USB flash driver, TF card or pair with Bluetooth FM transmitter(named T25) with your digital device to enjoy music or hands-free conversation. 3 Music Play Modes: With CVC noise cancellation technology, you can enjoy the crystal clear full duplex sound, you could enjoy music via 3 methods: 1).Play music from Bluetooth-enabled devices; 2).Stream music from SD card(32GB). MP3, WAV, WMA, FLAC, APE format supported; 3).Transmit music from USB flash drive(32GB). Hands-Free Calling & Navigation Broadcast: One click the MFB button to answer/redial/hang up or reject calls; Seamlessly switches between incoming calls and music. Besides, this fm transmitter supports existed navigation App on your phone, you do not need to look down the phone to ensure safe driving. Car Battery Voltage Detection & Blue Ambient Light: The FM transmitter will display cars voltage when plugged into the cigarette lighter. Keep abreast of car battery health at all times to avoid problems when driving. With the circle of blue backlight at the bottom greatly simplifies your operation for safer driving. Wider Range & Compatibility: This Bluetooth transmitter is well compatible with iPhone, iPad, Samsung, HTC, Blackberry, Sony, Tablet and other Bluetooth enabled devices such as MP3, MP4 Player. Also, with the wider range from 87.5MHz - 108 MHz, you can get more stable and consequent music experience without interference.