TechnoHooks B300 Bluetooth FM transmitter and Charger With 3-in-1 Charging cable --- everything you need in the car 
Specifications:
1, Dual USB Output Fast Charging with high-quality Multi 3-in-1 USB charge cable (Charging only, Can’t Transfer Data)
2, Bluetooth 4.2 compatible with Android & iOS, auto-connect, Stable connection 
3, Built-in high sensitivity microphone, One-touch hands-free calling
4, Unique digital display, display car voltage when plugged in
5, Support Bluetooth Music, micro SD Card/U disk up to 32GB in MP3/WMA/FLAC/WAV/APE format
6, Crystal sound quality, listen to music, navigation, broadcast and phone calls clearly
7, FM Frequency: 87.5MHz - 108.0MHZ
8, Input: DC 12V-24V, charging port output DC5V 2.4A MAX

How To Use?
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, SD card or pair with Bluetooth FM transmitter(‘named B300’) with your digital device to enjoy music or hands-free conversation.

Note:
1.When using, please find an empty station firstly and keep the FM transmitter and car FM radio at the same frequency.
2.Please change another stable channel if it has a lot of static or noise for the frequency conflict.
3.SD card and USB disk can support MP3, WMA, WAV, FLAC, APE format, if there is no USB disk and SD card, then just try the Bluetooth or fm frequency.

Package Included:
1x B300 Bluetooth FM transmitter
1x User Manual
1x 3-in-1 Charging cable