Its for the Czech zb vz26 magazines
It has a "945" stamp, most likely the year.
Sweet, that means it saw some action.
This item is located in Romania. I own a zb37 ammo box, also found in Romania. About zb37 I know it was used by polizei or waffen ss divisions only.
Was zb26 in general use, or was it more exclusively assigned?
I have found the same boxes in Finland used by SS nord