Amethyst - 925 Sterling Silver & Bioplastic Tragus Piercing Earring Stud or Labret Lip Ring This item of body jewelry is suitable for tragus piercings, labret, lip and monroe piercings. These bioflex tragus piercing studs are made from hypoallergenic acrylic. This piercing jewelry is thread less, the .925 sterling silver charm pops into the bioflex barbell. The barbell gauge is 18G, and the length is 5/16”, however the length can actually be trimmed down to the perfect size using a sharp pair of scissors. This makes these items very comfortable as they will custom fit your piercing.