Ring of O
The Ring of O is a specially designed ring which has been worn as a distinctive mark among BDSM practitioners, mainly in continental Europe — and especially the German-speaking countries — since the 1990s. Its use is relatively widespread within this subculture. Its name derives from the name of the central character in the classic BDSM novel Story of O (written by Anne Desclos using the name Pauline Réage), who wore an analogous ring.
The first image of this jewellery design was published in the September issue (No.4) of the German BDSM magazine Schlagzeilen in 1989.