This is something that would be configured by a given service (police, care workers, security companies etc) and issued to people who would be unable to use a phone either through ability or security and have it always with them. The service would have there own backend with stored information on the end user. The main feature is that it could be carried for months or years without needing to be charged, so no issues with system crashing, taking forever to get the app loaded or your phone battery dying because you went on Netflix for an hour. It is basically a panic button much like the red cords dotted throughout the homes of elderly and disabled people in the UK, but providing the same service further afield by reaching out on 'all available frequencies'.