This applications has being designed as a tool to find what is the current size of a physical ring in different standards from around the world and that will be updating with following releases.
This measure will be shown in three different values internal perimeter length, internal diameter and the actual size in the selected standard.
The measurements can be selected to be shown in metric standard or in inches by checking or unchecking the "in metric" checkbox. This will show the measurements in millimeters when it is checked and in inches when it is unchecked, as well the ruler will change its markers based on the selected standard.
For some standards we have extra sizes that will be shown just when the user check the "extra sizes" checkbox.