The app I use is free, very simple, and has places to fill in the info any emergency worker needs to know. My name and address, my emergency contacts, if I have any medical conditions, if I take any medications and if so - which ones. All very important if you are in an accident or collapsed because of some kind of physical problem. I was never sure whether first responders would actually use that type of thing, but they do. It's not silly to have one on your phone, and very well could save your life.