It is a MP3 player, Bluetooth stereo and Car charger, one device combines three function
5 EQ option for MP3 music at Natural,Rock,Pop,Classic,Jazz, support USB disk, Micro SD card, AUX connection
Wireless transmit phone call to car FM stereo system, capable for hands free phone calls, one click to answer/reject/redial calls
USB charges for Iphone/Ipad and other mobile device through Dual USB outputs: 2.4mAh and 1mAh specific for Ipad and Iphone

FM Transmitter function:
1. Plug this unit into vehicle cigarette lighter or power port
2. Tune radio to an unused FM frequency, then match the same frequency on the unit
3. Insert a USB disk or Micro SD card which contains MP3 music files, it will play and transmit MP3 music automatically through car stereo system
4. Extended music source through AUX port connection

Bluetooth function
1. Pair mobile phone with this unit. When mobile phone detects this unit (namely "BT20"), please pair and connect with password "0000"
2. This unit will automatically switch to telephone mode when phone call coming

USB charger function:
USB charges for Iphone/Ipad and other mobile device through output: DC 5V/2.1A

Specifications:
Bluetooth version: AC IC V2.1
Bluetooth Protocol: ADRCP HFP A2DP
Frequency Range:87.5-108MHZ
Frequency stability:±10ppml
Product lnput:12-24V
Music Format :MP3,WMA
Micro SD Card (Max capacity):32G
USB Disk (Max capacity)32G
Product Total Output:5V/3.4A
Color:Gray
Package:
1*Bluetooth FM transmitter
1*User manual