This Blue Titanium Captive Ring is made of ASTM F-136 implant grade titanium, with an anodized blue finish. Available in 16G, 14G with inner diameters of 1/4"(6mm), 3/8"(10mm), 1/2"(12mm), and 9/16"(14mm), and ball sizes of 3mm, 4mm, and 5mm. This ring is sold individually, so to purchase a pair, make sure to select a quantity of two.