Silver Maxi 5mm Round Ball Studs Ear Piercing Earrings "Studex System 75" Hypoallergenic NEW in Sealed, Sterilize Blister Package. Easily removed from self-piercing cartridge for use in already pierced ears. Made in the USA 5mm Round Ball Studs Hypoallergenic, polished surgical stainless steel One (1) pair with backs - Backs do not lock.