This diagnostic kit gives you everything you need to make sure your USB devices are getting the proper charge. The diagnostic kit lets you monitor the voltage and current being delivered to your device while it's charging, which makes it easy to test different power supplies such as wall and car chargers, computer USB ports, mobile charging banks, and charging stations. It's the perfect diagnostic tool for any test lab or repair facility, because you can monitor the current and voltage consumption of your Apple or Android devices against various power supplies, in order to determine if there's an issue with a specific charger, cable or battery. Plus, if you have several mobile devices at home and at the office, this adapter can help you to better understand your power requirements. Now, it's easy to decide which chargers and cables work best for each of your devices, so that you can charge at optimal speed and be ready when you need to be. You can set the tester to either display the voltage or the current reading, depending on your preference. You can also set it to alternate between showing the voltage and the current, so you can keep an eye on both measurements without having to adjust the tester. You can quickly charge your devices using the adapter's built-in fast-charge feature, when you're charging your devices from a USB port on your laptop computer. The adapter speeds up charge time by transforming your computer USB host port into a charge-only port, enabling you to charge your mobile devices as if you were using AC wall charger. You can also use the adapter as if it were a standard USB cable connected between your mobile device and your computer, which enables you to sync your device with your computer. Note: You can still charge your device even while it's syncing, but it might charge at a slower rate.