Measuring ring size is always a problem if you want to buy a ring online. An example of a ring buy from a goldsmith is that the size you ordered will also be the size you will get, but then you must provide the correct ring size.

The Multisizer works like a belt. Simply twist it around and insert the end of the buckle to form a ring shape. Slide the Multisiser onto the finger. Adjust it until it is comfortable. Check that it slides over the joints of the finger without difficulty. Now you only need to read the indicated size for the best fit on the finger.