This app is an app that allows you to use TONE's services safely and securely by checking whether the device you plan to use can be used with Tone Mobile.
If the device is determined to be compatible with the "TONE Compatibility Confirmation" app, you will be able to obtain an application number, which is required when changing the model of your TONE for Android plan.
You can check the details of the model change here.
https://tone.ne.jp/service/change/