Here's a set of 3 different Saint Christopher stamped medals. The largest one measures 2 1/2 inches in diameter. These are for dashboard mount.
My Italian grandparents had one of these with a pin back on the drivers side visor AND a plastic Jesus that glowed in the dark suction cupped to the top of the dash. I always felt doubly tight with God when Gramps took us out for a sunday drive in the country.

"I don't care if it rains or freezes cause I got my plastic Jesus sitting on the dashboard of my car. Comes in colors pink and pleasant, glows in the dark cause it's iridescent, take it with you when you travel far."

And I didn't even have to look up the lyrics. Also, don't forget about Magentic Mary.