Specification: Bluetooth version: V4.2 + A2DP Frequency range: 87.5-108.0MHz Frequency stability: 10ppml Product Input: 12-24V Charger output: Quick 3.0 Fast Charger, 5V/2.4A Music Format: MP3/WMA TF Card Max capacity: 32GB FM Transmit Distance: about 2-3M Bluetooth Distance: about 5-10M Features: Wireless transmit phone call from Bluetooth mobile phone to the car FM stereo system Dual USB charging ports: QC3.0 + 5V 2.4A, Suitable for iPod/iPhone/iPad and other mobiles, save time Real-time monitor of the car battery voltage, the voltage of the car will display on the FM transmitter after you start the car, the alarm will warn you if the voltage under 12V. Mobile navigation information broadcast, make is clearer without looking the phone screen, safer driving experience With automatically calling-number system Support TF card (MP3/WMA format, MAX 32G), A2DP function Strong and elegant design with white letter display, easier to look in night Auto-switch between music playing mode and Bluetooth hands free mode Flexible metallic hose can be banded and adapted for any type of autos Draws power from cigarette sockets in the car 12-24V 1.7'' large screen make it easier to look the letters. Goose Neck Design: Flexible metal hose, Convenient to adjust its direction and find better viewing Support SIRI Function: Long Press the big button 2 seconds to open the function. Note: 1. Suggest that RAM less than 32GB. Larger than 32GB which may cause the abnormal reading. 2. To protect this device, we recommend to remove it from cigarette outlet after use, to avoid instant high start voltage damage the FM transmitter. 3. If you want to charge the phone and listen to the car radio at the same time, please note that your radio frequency and our device's frequency do not get too close.