With a 3/4 inch diameter, the metal Marvel POW Dog Collar Charm displays a famous onomatopoeia that came to us from the likes of comic books and Adam West's Batman! See, that's all I had to say and you already know what onomatopoeia means! Get to learn something everyday, ya know? Lessons aside, the Marvel POW Dog Collar Charm is a charm that goes great with any collar, and immediately turns your dog into a superhero(even though they already are). Does not come with a ring or string to attach to said collar.