What are these called?

[lovesvintage]

Hi
I was wondering what these are called, they are for putting through the loop on removable buttons to fasten them to clothing and I need to buy some more if I can but I have no idea what they are called. They are 3/4in long.
TIA

 

[lkranieri]

In many places I see them referred to as button clips or shank button clips.

 

[The Vintage Merchant]

we call them cotter pins here in the midwest.

 

[Vinclothes]

Yes, Mary. That was the term I was trying to remember. Huge ones were on a trailer hitch I once had.
Marian

 

[Vinclothes]

Cotter pins in different sizes are still made today.
Marian