In Castilian Spanish it's called "imperdible" which means unlossable/unmissable, which results in the ironic occurrence of finding a lost one or losing yours.

I have a huge (4 inches/10 cm) brass safety pin with a number stamped into it. Apparently these were once used to tag bags of laundry in the military and industry.

"zicherka" (how is it called in your country?)

Its history is impressive but I used safety pin maybe few times in my lifetime and fail to see a single practical use nowadays, opposite to e.g. matchstick.

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