Each individual obstacle file (.ob2) is a combined obstacle database and license key. The license key ties the obstacle database to a specific device (model and serial number). If you try to install the obstacle database in another device, you will get an error.
If you have an avionics system with an integrated FLARM, note that the serial number to use when purchasing the obstacle database is the internal FLARM serial number, as clearly stated on the obstacle database purchase page. You should not enter the serial number of the avionics system. In some cases, the avionics system uses a similar serial number as the internal FLARM serial number. You can normally access the internal FLARM serial number under a configuration or information menu.