The magnets are 1/4" thick and 1" in diameter (I corrected the earlier post). When you stick them to the metal body, they are not magnetic to the coils. They are ceramic magnets so they won't rust. Although I'm fine with one on each side, if you still have an issue or it needs more thickness just add another magnet to each side. The pennies and nickels aren't enough, the plastic bumpers are too soft; you need a hard surface like these magnets for the hatch springs to bounce off of that is higher than the stock body with no drilling, gluing, sticky adhesive or modification of any kind. Here is a pic of the magnets:
