Note: The American sizes are based on numbers
1 - 15, with half sizes and quarter sizes (eg. 6.5, 8.25). One half size in US is
roughly equivalent to one whole size UK. In the UK, sizes are measured by alphabetical
letter A - Z although it is often necessary to go above size Z by appending ' Z+1,
Z+2, Z+3,' etc. The sizes are evenly spaced with half sizes. The European (EU) sizes
are based on the inner circumferential measurement of the ring in millimeters .