OKRAY USB Digital Multimeter Meter Power Tester, Current Voltage Battery Monitor, Test Speed of Chargers, Cables, Capacity of Portable Power Bank and More (Black) LCD Display Multi Meter: OKRAYs USB Security Tester can clearly monitor the voltage, current, energy, capacity, temperature and charging time via your cellphone and other usb devices. Its very useful and handy tool to measure the quality and continuity of your usb device at work. Measuring Range: Voltage: 3.0V-30V; Current: 0-5.1A; Capacity: 0-99999mah; Timing: 0-999hours; Power: 0-300W; Charge Accumulation: 0-999999MWH. Accuracy: +/- 1%. Real-time Charging Data Detector: It will record time once you use it. Within this data, you can clearly know the working condition of your devices (how fast to charge or how much time to get full power).Whats more, it will issue alarm if the device is full charged for effectively protecting device. Double Reversible USB Port: Exclusive design makes it easy to plug without checking for the connector orientation and meets your expectation on Data Sync and Battery Charging. It is perfect for using with your device safely. 24 MONTH WARRANTY: OKRAY 100% stands behind our products. If your new power charger cant meet your expectation, just let us know - via Amazon! OKARY Customer Support will help within 24-Hours.