SD Maid is an app and file management tool that helps you to keep your device clean and tidy. This app unlocks the "Pro" status in the free version of SD Maid, enabling all additional features. This is not a stand-alone app. You still need to install the free version of SD Maid. I don't mind a quick mail if you have questions. If you are unhappy with your purchase, mail me within a week and ask for a refund.