Internally threaded belly button rings are the optimum choice for newer piercings. The threading is inside the bar and not visible from the outside, so it can't rub against the tender piercing. Most new piercings are performed with internally threaded belly button rings. They are easy to wear and easy to keep clean from bacteria. While internally threaded belly rings are not as cheap as externally threaded ones, they are more comfortable and less likely to accumulate bacteria around the threading, which can cause infection. This premium belly ring is made of solid titanium with matching duo 4mm gem balls, each with a cubic zirconia crystal-clear gemstone. Both balls are fully removable, making the application process that little bit easier. The belly bar is dressed with matching 4mm/3mm duo balls with a press-fit gem. SOLID TITANIUM 6AL-4V-ELI ASTM F-136