The magnets are really incredibly strong for as little midgets. I use them sensibly to lock the frame to my Fliegengittertuer. Because of the small size, I could glue the magnet without any problems and the strength is more than sufficient strength to pull the door to the frame (for a total of 5 I use magnets).
But I have already broken 2 magnets. One of them struck me from a height of about 1 m onto a stone floor. The other has already been delivered damaged.
At 20 magnets and in terms of price but that was no problem for me at least.
