I’m guessing those are supermagnets. Fun stuff…they had a lab at the university I went to that forbid people wearing pacemakers from even entering because of these. These are the kinds of magnets that inspired the old cartoon gag of knives flying at you just because you’re holding a magnet.
“SuperMagnets are very large & powerful Neodymium magnets. They are strong enough to break arm bones and crush hands in the blink of an eye. The magnets listed as SuperMagnets can only be sold to adults and require an adult signature upon delivery. They are potentially extremely dangerous.
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SuperMagnets can only be shipped by UPS ground – they cannot be shipped via air as it will interfere with the aircraft’s navigational equipment.”