Holiday Shipping Details & Extended Holiday Returns 
Hands free calling: Only click phone&music botton, you can achieve the answer, hang up, reject or redial the income calls which free your hands and give you a safety drive. Freely switch to the incoming call mode when the music is playing.
QC 3.0 high-speed charging: With the QC3.0 usb charger port, could be high-speed charging of your electronic devices in a short time, compatible with smart phone, tablet, camera, kindle, sports watch,etc. Supports QC3.0/QC2.0/FCP/AFP.
One-key activated voice assistant: Keep pressing the phone&music button for 3s to activated the voice assistant like siri or google, help you to make the phone call/ send message or play music. It also supports voice navigation broadcast. Thoroughly provide you a safe driving.
Specifications:
- Bluetooth version: V5.0
- QC3.0 USB C port output: 5V/3A, 9V/2A 12V/1.5A
- U disk USB C port output: 5V/1A
- Intput: DC12-24V
- Support agreement: A2DP
- Frequency range: 87.5-108MHz
- Music format: MP3 / WMA / WAV / FLAC
- Fast charge protocol: Supports QC3.0/QC2.0/FCP/AFP
Support play your favorite songs by U Disk, TF Card and Bluetooth enabled devices, allows MP3 / WMA / WAV / FLAC format music.
Bluetooth 5.1 provides a stable and secure connection for a clear hands-free calls, reducing music delays and signal interruptions.
This compact design fits perfectly into most of car cigarette lighters. Compatible with most 12-24V vehicles like off road, car, truck, etc.
Turn on the car radio to a blank channel(it means unused FM frequency like 106 or 108Hz)
Plug the FM transmitter to car cigarettet lighter port, Long press the Next/FM key enter frequency mode: LED display flash, adjust the FM frequency to the same as the car radio FM frequecny by the Previous /Next button. The display flashes 3 times without any operation, exit the frequency selection.
Activate the bluetooth of your mobile phone, search the "BC57" and pair. Now you can enjoy the song from your phone.
1.When you are using it, there is lot of static and back noise interference, please adjust the volume on you car radio to a middle level, at the same time you could set the phone volume to the high level. That's way you able get the good quality sound.
2. It's common that the signal is affected by the local radio and the signal become weak when you driving or passing the signal tower, suggest you choose the unused and stable channel like 87.5Hz.