I was wearing it one Sunday afternoon to a football party, when my 10 year old son started having a panic attack that raised his blood pressure. We ran to the emergency room, and while he laid in bed, still crying, I gave him my key and asked him to breathe slowly and calmly, which he did. He held the key very tight, and started to calm down. We were able to leave the emergency room soon after, with my son feeling much better.
It is now his key, which he wears and when nervous, he remembers to breathe slowly...and feel fine.