This listing is for a single ASTM F136 implant grade titanium push-pin flat back stud with a zirconia stone.Measures at 1/4 in length (6mm post). 18 GA. Stone is 2mm.Metal Colors available: 18K Gold Plated Titanium, Titanium SilverPlease note that, as with all pronged earrings, there is a higher possibility of having them catch on things.*Please see site return policy for more information regarding flat back studs!