captive bead ring
A captive bead ring (ball closure ring) is a type of body piercing jewelry. The captive bead or ball fits into a small opening in the circle of the ring. The bead is slightly larger than this opening and has small indentations or depressions that correspond to the ring's end-points so that it may fit snugly against them, thus completing the circuit of the ring. Often, a hole is drilled through the bead to allow easier fitting.
Captive bead rings can also have little accessories.