Our child (2) got the good aunt Hohner in the fingers and understood very quickly how to produce sounds with it. Then he got her a toy harmonica given .. the sound is a difference of day and night! After his beloved toy harmonica was gone I was looking for a new harmonica Hohner this ... She's only 6 more expensive than the toy model, torturing my ears ... and sounds way better.
So when the child wants a harmonica, then prefer bit more to spend and ears conserve! :-)
Pretty small. Well packed in a box ... fits easily into any hand luggage! :-) Top!