These magnets are incredibly strong for their size. They come with double-sided adhesive paper so you can hang materials that are attracted by magnets to them. You have to be careful not to get them too tight (and they will!) because sometimes one of them can break. I believe the neodymium is nickel plated to improve its integrity but this is a very thin layer and not very good protection when the strength of these magnets allows them to hit each other. Speaking of which, be careful when playing with them. They can pinch if you're not careful, so I wouldn't give a child more than a few to play with (although it could potentially pose a choking hazard). But it brings back the fun of playing with magnets from my childhood, albeit 10 times stronger. Available magnets just weren't that strong when I was a kid :)
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