Vintage/antique French shirt studs, probably made in the early to mid 20th century.  Metal.  They will be supplied in a plain gift box.  The tops measure 12 mm across.  

Condition: Vintage shirt studs, many decades old, and still in serviceable condition, but past the first flush of youth, with surface marks, greening and discolouration from storage, as shown. They will need a clean/polish before use.