Features:Built-in Bluetooth Technology.Built-in Microphone for Hands-Free Phone Calls.USB Flash and Micro SD Card Readers.Quickly Plug-in and Play Your MP3/WMA Files.Hands-Free Mode Automatically Switches To Incoming Calls When Playing Music.Use the DSP (digital signal processing) echo cancellation technology and noise suppression (CVC) technology to create an excellent voice quality.Specifications:Material: ABS + UVSize: 48 x 80mm/1.89''x 3.15'' (Approx.)Bluetooth Version: V3.0 + EDRFrequency: 20 h20 KhzRated Working Voltage: 12V - 24VLimit Working Voltage: 9V - 26VUSB Charging Output: 5V - 1000mSupported Music Format: MP3/WMASNR: >60dBDistortion Factor: <0.1%Bluetooth Voice Processing: with the A2DP function (Advance Audio Distribution Profile)Transmission Range: 5MFM Transmission Frequency: 87.5 - 107.5MHzBenefit:Connect the Bluetooth Transmitter into your vehicles cigarette lighter to enable a wide range of multimedia options. Answer calls via Bluetooth、 play MP3 and WMA files with the built-in USB Flash drive and Micro SD Card Readers、 listen to your favorite FM Radio station、 and best of all、 do it all while you charge your device with the USB Charging Port conveniently located on the device.Enjoy the power and versatility of this compact and multi-functional Bluetooth FM Transmitter.Note:This device is compatible with most of the mobile phones、 except of a few mobile phone that are not available to use parts of above functions.Package Includes:1 x Bluetooth Hands-free Car Kit Car Charger MP3 Player1 x User Guide (English & Chinese)