Every charger in every shop needs to have this dual usb ammeter attached. Easy to read for your old Gramma eyes like Jessa. You can see a digital display of the charger voltage being put out by the charger, and the current consumption of the device as it charges. This tool is your first step to diagnosing charging issues in any mobile device. Rather than relying on the device itself to report charging, you can see for yourself whether or not charging is happening at all, and if so, is the device pulling a normal charging current, low or high? This tool can also be sold to customers as well---it can help them maximize the life of their device with a finicky charge port and avoid a costly repair. The usb ammeter will let you know right away if a device has made good connection with a charger by showing you real time current consumption.