A new Apple AirTag teardown video reveals that each one is packed with drivers, coils and (of course) button batteries. However, and possibly more importantly, it may also show that their clearly keenly developed appearance might degrade quickly over time with use. On the other hand, they can theoretically be torn down for repair (should the user want to do so) at least.
https://www.notebookcheck.net/Apple-s-AirTags-might-not-stay-as-shiny-as-they-look-right-now-throughout-their-working-lives.537458.0.html