The STANLEY PI500S power inverter provides on the go power with a lightweight, ergonomic design that charges up to 4 devices at the same time. Simply connect the clamps to your vehicle battery for 500 watt continuous power or plug the power cord into your vehicle's 12V DC port (cigarette lighter) for 120 watt power inside your car. This power inverter is equipped with dual 120V AC electrical outlets and dual 3.1 Amp USB ports, allowing you to charge and power smartphones, tablets, laptops, tools, and more from just about anywhere. It features built-in battery protection warning, indicating when the vehicle battery is running low. Plus, the over-voltage 100 watt protection allows you to avoid blown fuses.