Nebula is a concept, designed by Polygon, its innovation and design, lies in the change of state from the pure geometric form and completely smooth complex geometry reminiscent of the nebulous space, the transition of the ground state and of the creation of galessie eternal transformation of the universe. It 's the matter itself is transformed. Model: Diamond Bird Size: 16.5 mm (inside diameter in millimeter. For international sizes check http://en.wikipedia.org/wiki/Ring_size) If you are interested in different sizes or materials, please contact us and request your size or desired material. Polygon