The Extech’s USB200 monitors voltage, current, and charge capacity (mAh) to determine the quality and stability of chargers, power banks, and cables. It’s designed with a standard USB-A connector to plug into a device to be measured. It also has a USB input to test the quality of charging cables by observing the displayed current. The USB Power Monitor measures the output voltage, current, capacity and stability to prolong the charging equipment’s life cycle and memory stores up to 10 readings. Includes protective USB plug cover for storage.