The Bluetooth FM transmitter features 2 USB ports. 5V/2.4A for charging and 5V/1A (with music symbol) for detecting USB stick or charging. Charge 2 devices simultaneously. Car battery voltage display and ambient light: the transmitter displays the vehicle voltage once connected to the car cigarette lighter, allowing you to monitor the car battery condition. The blue light circle simplifies operation for safe driving. Wide compatibility: this hands-free kit pairs with any Bluetooth device. Compatible with iPhone, iPad, Samsung, HTC, Blackberry, Sony, Tablet, and other Bluetooth-enabled devices such as MP3 and MP4 players. With a frequency range from 87.5 MHz to 108 MHz, you enjoy a more stable and interference-free music experience. This Bluetooth V5.0 FM transmitter includes 6 colored ambient lights that can be switched to green, red, blue, yellow, cyan, or purple. The 6 colorful LED breathing lights enhance your car's interior style and make nighttime operation easier and safer, adding more enjoyment to your drive.