I own a MagSafe charger and unless the author added a third party black case (?) around the puck, then that’s not a real MagSafe charger. I haven’t heard of cases for it but that doesn’t mean they’re not common, of course.
From the article: "However, I have already bought this product and the other pieces for my car mount."
The black ring is probably one of the "other pieces for my car mount".