This device is used for male constraint/adornment.
It consists of a series of nickel-plated steel rings connected by a leather strap. The first, largest ring goes over the cock and balls, and the cock alone goes into the other rings.
The rings get progressively smaller, confining the penis. This 5 ring version starts with a 1¾\ » ring, followed by two 1½\ » rings and two 1¼\ » rings. The entire length is about 3\ ».