When I was in Korea my 엄마 (Omma) and 아빠 (Appa) gave me this phone charm. These are popular in Korea and come in a variety of styles and sizes. Some are even subway tokens that track money for your fare which I don’t have, but might get the next time I am there, since I rode the subway a lot when I was in Seoul.
A lot of asian brand phones (like Nokia) have the little holes on the phone body for these, but the iPhone does not. So I attached it to one of the openings where the headphone jack goes on the case and it has lived there since I got it.
Now I can’t imagine my phone without it! ^^