ThisWhite Opalite Circular Stainless Steel Horseshoe Barbell is made with high-quality 316L stainless steel and syntheticwhite opal gems. The barbell is available in 16G and 14G sizes, and comes with 3mm and 4mm ball sizes. It has 5/16" (8mm), 3/8" (10mm), and 1/2" (12mm) inner diameter sizes for a comfortable fit, and is intended for healed piercings.