The `@region` attribute defines which area of responsibility a feature belongs to.
The `@region` attribute defines which area of responsibility a feature belongs to and may be set to any [valid region](/Regions).
:warning: The `@region` attribute has to be set on the `*Uid` element!
Regions are either an individual FIR (e.g. "LSAS" – the one and only FIR in Switzerland) or a group of FIRs (e.g. "LF" – the composition of all five FIRs of Metropolitan France). In other words: Regions are not always equivalent to FIRs!</dd>
**LQSB** | LQSB | BA :flag_ba: | Bosnia & Herzegovina :construction:
**LRBB** | LRBB | RO :flag_ro: | Romania
**LSAS** | LSAS | CH :flag_ch: | Switzerland
**LYBA** | LYBA | RS :flag_rs: | Serbia :construction:
**LZBB** | LZBB | SK :flag_sk: | Slovakia
**UGGG** | UGGG | GE :flag_ge: | Georgia :construction:
Furthermore, inter-regional objects such as borders or international airspaces may use the pseudo region `ZZ` if no other region is suitable.
### @mid
Since `*Uid` elements may contain many attributes and key properties, comparing them is challenging at times. Optional `@mid` attributes facilitate this by adding a unique fingerprint to the corresponding `*Uid` element.