With the Mobile Charging Checker, you will be able to see how your device is charging as it is being charged. Simply plug the USB end of your charging cable into the Mobile Charging Checker and then the other end of the checker into a USB port on your computer or into the USP port on a Wall Charger. As your phone begins to charge, the display area on the checker will start to display 3 different sets of number. One number will be the charging voltage, a second set of numbers will be the charging current, and the third set of numbers will be how much percentage your device has currently charged since being plugged in. For imprinting options, you will be able to imprint your logo on the back of the Mobile Charging Checker.