This a diagrammatic representation of a deoxyribonucleic acid molecule made into the form of a ring. More specifically, it is a representation of Z-DNA, which forms a left-handed helix. To buy a normal B-DNA representation, as first described by Watson and Crick and having a right-handed helix, go here and a heart version here.
This is a US ring size 6, which is 0.65 inches or 16.5 mm inside diameter; other sizes can be created upon request.
Rough design and photography by Cheri Cloninger. Detailed design and 3D modeling by James William Kincaid III.