Sizing beads (sometimes called sizing balls) are small metal beads added to the inside of a ring band to help the ring fit more snugly without permanently resizing the entire shank. They’re especially useful when a ring spins on the finger due to larger knuckles, weight changes, or top-heavy settings.
Because sizing beads reduce the interior diameter only slightly, they can be a comfortable, reversible alternative to a traditional resize—particularly for rings that can’t easily be sized (for example, eternity bands, intricate designs, or pieces with stones set all the way around).
A jeweler typically solders two small beads to the inside of the band and smooths them for comfort. If needed later, the beads can often be removed or adjusted.