1.Dual USB ports: This FM transmitter has 2 USB ports: one is designed for charging the other one is for reading USB files. This feature enables you to play music and charge your phone or other devices simultaneously.2.3 playing modes: This FM transmitter supports 3 playing sources: ,Bluetooth-compatible, TF card, USB flash drive.3.Crystal sound effect: This FM transmitter utilizes the most advanced interference and noise cancellation technology, which provides crystal sound quality and more stable signal.4.Other functions: Built-in microphone feature supports hands-free talking; support TF/Micro SD Card in FAT format up to 32G; support A2DP; support MP3/WMA format; support AUX output and input.5.Easy to use: Easy pairing with Bluetooth-compatible stereo headset, headphones, speakers and other Bluetooth-compatible stereo audio enabled system. It will pair automatically after you power on.