It may be a form of medical alert device that you were not aware of, but you can choose a medical alert watch as opposed to the more traditional forms such as necklaces, bracelets and charms.  These are worn like a piece of fashionable jewelry with two purposes:  the first is to save your life if you have a medical condition and the second is to tell time like a classic timepiece.  This is a great way to combine two important pieces of jewelry into one and is especially popular for those who do not wish to advertise their conditions.