Hands-Free Calls: Vehicle FM transmitter is equipped with built-in microphone and CVC (Clear Voice Capture) technique to offer clear and fluent calls, making you drive more safely. By pressing or rotating the button to realize incoming call answering/redial/hanging up/rejecting and so on. . QC3.0 & Dual USB Vehicle Charger: This type of new-fashioned and cool wireless Bluetooth vehicle transmitter is equipped with two charging QC3.0 interfaces in 5V/1A, supporting two devices to charge simultaneously. Smart QC3.0 USB can load compatible devices up to twice as much as traditional chargers speed. LCD display screen can show the volume, vehicle voltage and frequency clearly. . Portable and Easy to Use: Insert HOLALEI Bluetooth FM transmitter into the vehicle cigar lighter. Turn Bluetooth telematics to a vacant FM frequency, and configure the same frequency (87.5-108 MHz) on transmitter. After connecting with phone or tablet computer by Bluetooth, you can listen in your favorite songs or GPS voice route navigation. . Multiple Security Protection: FM transmitter is equipped with a built-in smart chip (charging IC) that distributes voltage automatically in accordance with the requirement of device. It is provided with built-in over current protection, over voltage protection, smart temperature control and short-circuit protection. Bluetooth FM transmitter can prevent from a number of insecure problems effectively, letting you understand the state of battery voltage so as to guarantee your driving safety. . Extensive Compatibility: FM vehicle Bluetooth in version 5.0 is compatible with Bluetooth versions in Android and iOS system. Through FM signal, transfer music, from USB flash disk or Micro SD card, to vehicle audio electronics to play, and it can load the capacity of USB flash disk or Micro SD card up to 32G. Moreover, we provide you with 1 month of unconditional refund and 12 months of free replacement. In case of any questions, please contact the shop customer service. .