Upon opening the package the product itself is disassembled. While there are no instructions it is not difficult to figure out how to attach the magnet to the suction cup base. It comes with 1 rectangle metal plate and 1 circle metal plate with adhesive on the back. I tried both, the rectangle plate inside of my wife's phone case as well as the circle plate on the outside of my phone case. With the plate inside my wife's phone case the magnet seemed to hold but not as easily as if the plate was on the outside. I don't think it would work well with thicker phone cases. It does hold very well even going over speed bumps and fast driving. Overall a very good product.