The first necessity to choose the right ring is to select the right fit. Here is the best way to do it: Find a piece of string that is about six inches in length. If you do not have string, you can really choose anything like a thin strip of paper, tissue, cords, etc. Anything that can wrap around your finger will work. Wrap the string around your finger. Use a pen to make a mark where the end of the string meets. Find a ruler and measure the string. Take your answer and subtract 9.3 from it. Round to either .0 or .5, and you got it!