Aduro U-Grip Universal Magnetic Vent

So if you don’t use a phone case, does the magnet attach directly to your phone?

Depends on if your phone case is a magnetic metal.

“Includes 2 Rectangular and 2 Round Adhesive plates”

If magnets aren’t attracted to your phone, you need to use one of the supplied adhesive backed plates stuck on the back of your phone. I use the round one on my iPhone. It’s 1.5" in diameter and very thin.