Even better: KM19 updated with more Features. Now you are able to play music through the USB disk, TF card, Bluetooth and AUX cable Compatibility: works on most devices on the market (Apple, Google, Huawei, Samsung, Sony and others) Big LCD display: 1.44 inch screen to better visualize your phone calls, music, car battery voltage TECHNOLOGY IN YOUR CAR: With our device you will add in your car: 1) Bluetooth connection; 2) Answer phone calls safely with the press of a button while driving; 3) Voltmeter function to control the quality of your car battery; 4) 4 different ways to play Voltmeter function: safety when driving is our first concern, so we equip our devices with voltmeter. You can now check the car voltage before your trip or daily ride