Charm or pendant bail in stainless steel. Also called hanger links. They have a 1.8mm with a 2mm loop for dangles. Feed this onto chain or cord and dangle a pendant or charm from the loop.
Note that if you want to use this with a chain it needs to be thinner than 1.8mm as that is the size of the hole.
Dimensions: 6mm wide, 9mm tall (including the 2mm loop).