Annulets as regular charges (not as a difference). Gules, three annulets in pile Argent
In heraldry, an annulet (i.e. "little ring") is a common charge. It may allude to the custom of prelates to receive their investiture per baculum et annulum ('by rod and ring'). In English heraldry it is also used as the difference mark of a fifth son.
This article incorporates content from the 1728 