【Bluetooth hands-free system 】 Advanced Bluetooth 4.2 technology enables more stable connection and faster transmission. Built-in microphone with CVC noise reduction technology gives you crystal clear hands-free function after Bluetooth connection. 【Multi-Music Playback Modes 】 Enjoy lossless stereo music transmission. The FM transmitter can play your favorite music from Bluetooth devices via FM signals to car stereos. The USB drive can be used to transfer and play MP3/WMA songs. 【Quick Charge Smart QC 3.0 】The Bluetooth auto transmitter has two USB ports and can charge two devices at the same time. One is USB QC 3.0 port for fast charging, 4x faster than standard chargers. (Compatible with: QC2.0, Hua Wei FCP, Samsung and HTC.) 【Easy operation】 ① - Plug this Bluetooth FM transmitter into the cigarette lighter socket. ②-Turn on the car FM radio and select an empty frequency. ③-Then set it to the same frequency on the transmitter (87.5-108.0MHz). ④-Connect your mobile phone to the transmitter (name C57) via Bluetooth. With the wider frequency from 87.5MHz to 108.0MHz, you can get a more stable and consistent music experience without interference 【Multiple protection and customer service 】Comes with built-in intelligent IC, over current protection, over voltage protection, intelligent temperature control and short circuit protection. Specifications Built-in microphone with CVC technology for clear conversation. Connect your phone to the car radio wirelessly. A USB music port to connect a USB flash driver (max. capacity 64 GB). A USB port to charge QC 3.0 and quickly charge the phone. LED Display: Shows the FM band for you to tune it easily. Provide hands-free calling and a safe driving experience. Technical Data Input: DC 12~24V Frequency Range: 87.5~108.0 MHz Bluetooth Version: ATS2815 V4.2 Heating low voltage: LED flashing at less than 12V Music format: MP3, WMA, WAV Product weight: 37g Multi-music playback modes Play music via Bluetooth-enabled device or USB flash drive, excellent built-in microphone with echo cancellation noise reduction (CVC) technology, enjoy lossless stereo music transmission while driving Free Bluetooth With more stable FM signal, built-in microphone with echo cancellation noise reduction (CVC) technology, this FM transmitter let you speak clearly. Drive safely.