My little girl has been wearing her medical alter tag since she was 6 months old. I sent for the smallest one it was to big for her wrist but it fit really well on her ankle and it fits snug if your child is wearing socks and it will not slide off. Once she got older I did have some of the links removed (actually i did it myself with a pair of small plyers) and now she wears it on her wrist. It does not bother her and she has never scratched herself with it at all.

Tina