Internally Threaded Labret with Bolt & Nut Top 316L Surgical Steel Mirror finished Implant Grade 316L Surgical Steel Labret/Monroe with a Bolt & Nut top. Internally Threaded. Precision threading is silky smooth and locks securely. Material: High Quality 316L Surgical Steel 14GA, Length: 3/8" Ball Size: 8mm Available in 4 sizes!