This is what in on my son's necklace:  Adrenal Insufficiency needs hydrocortidsone in stress.  See card on parent/child.

We have a necklace that is 2 disks together and the inscription is on the inside.  I wasn't totally sold on it when I bought it, but I'm glad we got it.  With the engraving on the inside it prevents it from getting scratched and more difficult to read.  I bought it at a jeweler's and it cost approximately $40.  The card I refer to has detailed info on it:  Name, address, emergency numbers, doctors numbers and emergency instructions.  Cody has one on his bookbag and my husband and I keep one in our wallets.

I hope this was helpful.