A customer has complained here about the power of magnets ... this may be just a mistake. I have done the test: A single magnet holds 9 DIN A-4 sheets of my printer paper, the 10th sheet, the stack will begin to slide, but the magnet does not fall down (!). This force do you get to feel shortly after shipping. The magnets arrived in a padded envelope and already prepared my postman a surprise when the envelope was connected to his car door. When taking out the small problem I had to separate the 3 rolls interconnected pieces.
Conclusion: Very strong, tiny magnets that can be solved only with some power back from the metal. Thus, they are intended for discreet, because of chrome color even stylish, holder for pictures or various other items.