This app purpose is to automatically run a user defined app each time a specific USB device is plugged to your Android. You can set general rules, like "Any USB device", or more specific rules, like "USB mass storage devices", or even set rules for a specific device. If there are multiple rules set, the one that will be executed is the more specific one. In free version, to try out the app, you can only define one rule. Also, ads are shown.