It is most common to have 2-3 forms of medical alert Identification. Typically a medical alert ID bracelet along with a medical Identification alert wallet card is the most common.
Your medical bracelet will provide your most important information up front and right away. (also paramedics look for medical alert ID bracelets right away) than carry a medical alert ID wallet card to list your contact info, Emergency contacts, medications, and any other information that was unable to fit on your current medical jewelry.
Medical ID wallet cards are very common but should not be used with out a bracelet or at least a necklace. (just to be safe, in-case a professional does not find your wallet card or does not look right away) My-Identity-Doctor.com provides a free 2 sided medical wallet card with all purchases. You can also print your own medical card online for free as well !
Remember it is your responsibility and very important to always have the correct information and to keep it up to date. Always speak with your physician if you are unsure about the information you have on your medical ID.
It is also your responsibility to make sure your engraving has not faded or worn off. This should be checked regularly as your ID jewelry ages.