Features: Rated operating voltage: DC12V-24V Working Voltage limits: 9-26V USB Output: 5V/2.1A Working Temp: 0-50 Support Play format: MP3 BT Version: Version 3.0+EDR Bluetooth sound processing: A2DP(Advance Audio Distribution Profile) Bluetooth transmission distance: 10M Bluetooth microphone effective range: 0.5-2M FM transmission frequency: 87.5-108Mhz User Tips: 1.It is a normal phenomenon that FM product will have some noise because of the interference of the local radio signal.Find a vacant or non-interfered frequency and sync the device to that frequency for minimized static noise. 2.To achieve best audio quality,please set the volume on your phone or the device to maximum and then adjust the volume for your car stereo;you are not suggested to adjust volume of your car speaker to maximum (this will bring lot noise). 3.Suggest that RAM less than 32GB. larger than 32GB which may cause the abnormal reading. 4.Our products support the use of 12-24V normal battery in the car/truck,we recommend that you do not use the product in car/truck that modified the battery.This may cause burned because of instantaneous high current. 5.To protect this device,we recommend to remove it from cigarette outlet after use,to avoid instant high start voltage damage the device. 6.