Worn brass component with conical threaded apex found

[panic]

Hello fellow enthusiasts.
Long time since i las visited the site, longer even tha I posted anything.

I went out today on a long walk in the rain and a short hunt at my local WW2 German coastal Bunker site here in Greece. I found only a few items (a partial brass casing, a 15cm piece of barbed wire, another thing, a plastic disc that I think is a gasmask's "antifogging inlay" (called a "Klarscheibe", I've made an enquiery about this at a related thread here: https://www.warrelics.eu/forum/field...nserts-260402/) and I found also this brass thing...

Check the photo composite attached below.

The ruler is in cm, the object's lenght is 2,3cm, the diameter of its backside(?) 0,9cm and the front hole's 0,4cm.



I have no clue what this is and would appreciate your expertise.