With me becoming an aviation enthusiast and AirBerlin becoming insolvent, my mom has gone on a hunt for deals on what I can best describe as AirBerlin merch (old uniforms, shirts, skirts, belts and many more).
In one of the packets that arrived recently she found items that neither her nor I knew the purpose of.
They are about 2cm * 2cm, yellow, have some kind of number on them and on most of them was the writing "Air-Berlin SEALED" or "airberlin group SEALED" and an engraved "PULL". It also looks like you can break off and bend a part in the plastic to the back and clip it there.
Below is a picture I took of a few of these:
If there are any tags you see fit, please add them; I have not a whole lot of ideas what might be useful here :)