Liechtensteinian Postal Codes
History
The German-speaking nations have an informal (and decreasingly utilized) system of prefixing postal codes with a country code. Liechtenstein's code was "FL", leading to postal codes like "FL-1234". (Germany used "D", Austria used "A", and Switzerland used "CH").
Specification
Liechtensteinian postal codes are 4 digits long (zero-padded).