you can always go to a jewelry store and ask for a saleslady. Most jewelry stores have their salespeople on hand to help you pick the right necklace for you. They may even be able to point you in the direction of a company that makes custom made ones too!
Since there are so many projection necklace products on the market, you may be wondering how you can tell which one is right for you. You can always check out some reviews online or ask around. Everyone's situation is different, so it's unlikely that one particular model will be the right one for you. Be patient and you should be able to find something that you absolutely love.