Ring Width is 20mm,thickness is 9.5mm,these two sizes are fixed. The size you can choose is ring’s diameter,there are 6 diameters optional:40/42.5/45/47.5/50/52.5, weight range from 100g to 190g. Advantages: stainless steel prevent rusty,mirror polished look beautiful,curve edge wearing comfortable Circumference/3.14=diameter For example,if the circumference of the area where this ring be worn is 141mm,then diameter is 45mm,when select the ring size,always select the smaller size,so 42.5mm and 40mm would be your options rather than 47.5mm. This is not a precision instrument, please accept a little dimensional errors on width and height that do not affect the use.