Built-in Surge Protection: Safely protect your electronics against power fluctuations from vehicle startup and shutdown Automatic-Shutdown: The device will automatically turn itself off to protect your battery from draining USB Charging Port:- Charge any consumer electronic device that can be charged via USB port. Ground Fault Circuit Interrupter (GFCI):Prevents shocks to an imbalance flow of energy from the Hot to Neutral contacts Power/Surge LED: Allows you to visually indicate the inverter's status. Cyberpower DC to AC Mobile Power Inverter - 400W CPS400AI Power Inverters