This 18 gauge septum jewelry is made with surgical grade 316L Stainless Steel and Titanium IP Plating for color. IP Plating (Ion Plating) is a safe and permanent surface refinishing process that produces a harder, brighter, more durable piece of jewelry. This ring has an 8 mm (5/16") diameter and 3 mm balls. This body piercing jewelry is hypoallergenic.