Buttons KUK for cloth curtain??...help please, found today

[U-21]

Hello guys, today I found these buttons (about 40 pieces), I think they are buttons KUK for the cloth curtain, but I'm not sure.
I ask you the information, many thanks in advance.

Regards
Uwe

[U-21]

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[Chip M]

Yes, those are the closure "toggles" for the Austro-Hungarian WWI (and later issues) Zeltplan. If you have the shelter canvas and it is missing some of these, they could come in handy. Fortunately, my example is complete.

Chip

[U-21]

Thanks a lot Chip!