I ordered these magnets, because I needed something to strengthen magnet for a cell phone pocket. Thus, my phone automatically locks when the bag is closed. The magnets are so strong that the phone itself in the unfolded state has locked itself.
So I have put several layers thick cardboard around the magnet (3 - Set of 4) until no more board fitted in the pocket. Nevertheless, the phone had responded to the magnet.
These magnets should not be underestimated, but I sent it back because it is not suitable for my purposes.