ThisPurplePVD Titanium Circular Barbell is precision handcrafted with ASTM F136 titanium. It is available in 16G with lengths of 5/16" (8mm) or 3/8" (10mm). The 5/16" length has 3mm balls and the 3/8" length has 4mm balls. The titanium is coated withPurple PVD for a beautiful, long-lasting finish. This barbell is designed for healed piercings and is internally threaded for a secure fit.