5 V / 2.4 A charging process and 5 V / 1A (with music symbol) charging port enable faster and more stable charging speed. Dual Port Charge Intelligent Distribution 3.4A Single port charge up to 3.4A. If the FM transmitter had Bluetooth, you can enjoy crystal clear music through 3 modes: Bluetooth, TF card (32GB) and USB stick (32GB). Supports music form: MP3, WAV, WMA, FLAC, APE. With this wireless device, you can conveniently answer / reject / redial calls with hands-free calling and drive safely. Noise and wind are suppressed by the CVC technology and ensure full duplex sound quality. The car transmitter shows the vehicle voltage as soon as it is connected to the car's cigarette lighter. Then you can know the car battery condition easily. Plug this wireless car kit into the cigarette lighter socket, tune the FM car radio to an empty station (87.5-108.0 MHz) and set the FM transmitter to the same station. Pair with your cell phone via bluetooth and enjoy your music.