Hinged Segment Hoop,16 gauge,Polished Stainless Steel,10mm, o.d., 8mm i.d.circular barbell,piercing ring, keeper bag, polish cloth 16 gauge hinged ring - 1 piece - 8mm inside diameter (about 5/16" inside), a 10mm outside Polished surgical stainless steel.INCLUDES Velvet Keeper Bag Hinge locks/snaps into place for seamless secure fit. 10mm outside, 8mm inside Septum piercings, ear piercings,nipple piercings. Where/how you use depends on your piercing sizem, location, and preference