These are a set of 3 rings that are interlocked- like the "puzzle" or "Russian" rings- but in which no ring actually passes through any other ring (unlike the "puzzle" rings). There's a link to the Wikipedia article on the concept on the page above.
The fun part of them is that they are GREAT to fidget with- they like being both in ring form, and in what i call "sphere" form, where they look like a wire-defined shpere, or maybe a graphic depiction of an atom. Fun stuff! and also really pretty.