55mm refers to a ring circumference of 55mm. Currently, there are four mainstream ring size standards in the market: mainland ring size, Hong Kong ring size, American ring size, and European ring size, all of which have a circumference of 55mm. The specific selection needs to be based on the comparison table used by the store.
Mainland version ring size comparison chart
According to the table below, the ring with a circumference of 55mm corresponds to the mainland version size 15 and a diameter of 17.5mm.
Hong Kong Ring Size Comparison Table
According to the table below, the ring with a circumference of 55mm corresponds to the Hong Kong version number 13 and a diameter of 16.5mm.
US Ring Size Comparison Table
According to the table below, the ring with a circumference of 55mm corresponds to a US size of around 7-8 and a diameter of 17.3mm~18.1mm.
European Ring Size Comparison Table
According to the table below, the ring with a circumference of 55mm corresponds to the European size 55 and a diameter of 17.51mm.
