Size 6 (US) L.5 (UK) (c=51.9mm)
Size 6.5 (US) M.5 (UK) (c=53.1mm)
Size 7 (US) N.5 (UK) (c=54.4mm)
A single twisted strip around the finger. Band width is 5.6mm, default inside diameter is 17mm (c=53.4mm), and the thickness is 1mm.
Although it says "Never Printed", the default size has actualy been printed in some of the plastics previously. (I had to reload the same file to make additional colors available.) Shapeways has previously rejected this design for printing in silver, however, for reasons I don't understand. You can try if you like, but it may be rejected again. (They cited "interlocking parts" initially, then wall thickness when I pointed out that it is one piece. The walls are thicker than the 0.8mm minimum for unsupported walls, however, and they didn't say how thick they thought they needed be.)