The Klein Tools ET910 is a USB digital meter and tester combination for most common USB-A ports, including Qualcomm Quick Charge® ports. It accurately and reliably measures and displays the USB port voltage, current, capacity, energy, and resistance simultaneously. It can also test the maximum current delivery capability of the USB port with built-in fixed loads so user need not connect to an external load. It will function with any USB-A port that has the ability to deliver power. It requires NO batteries as it draws power from the power source to function.