Quick bone conducting headphone advice: no top of ear pressure?

Fellow headphone junkies,

My wife wants some bone conducting headphones for Christmas so she can listen to her audiobooks from her iPhone, but she doesn't like headphones that press down on the top of her ears or are airbuds.

Since the music quality's not really an issue, do any of you know of some headphones for her that either rest on top of her head (like traditional oldschool headphones) or hold onto her head or something?