We have a 5month old baby and asked our Endo about the bracelet as well as how to identify that he was a child with CAH. He said some mothers had written on the car seat, however if the baby were thrown from the seat that wouldn't be of any use. When we called the bracelet people they said only on a limb. We are going to have two. One on the carseat strap near the hook-up part at the top and one on his arm .