1. Dual 2.1A USB Ports: The 2.1A dual car charger adapter charges 2 devices simultaneously. The car charger adapter provides overcharge, overvoltage, overcurrent, overheating and short circuit protection. 2. LED Voltmeter Display: The car charger has a built-in digital blue LED voltage monitor, which displays the real-time voltage status of your vehicle's battery to avoid problems caused by low voltage. The light also helps you quickly and easily find USB ports in the dark or at night. 3. Material: The 4.2A USB car charger is made of PC material, which is strong and sturdy, and will not overheat at high temperatures, non-flammable, good stability, and safer. 4. Easy Installation: This USB socket is easy to install. "+" is the positive pole, "-" is the negative pole. Certified by . With touch switch for easy operation. 5. Wide Compatibility: The 4.2A USB socket is suitable for 12/24V car, boat, marine, motorcycle, RV, etc. Suitable for charging mobile phone, GPS, digital camera and