Neodymium magnets are the strongest magnets that are commercially available.  Sometimes they are referred to as Rare Earth, Permanent or NdFeB magnets.  They are an alloy of Neodymium, Iron and Boron (NdFeB).  Unless otherwise noted, these magnets will have a triple plating of Nickel-Copper-Nickel.

Super cool 1/4" cubes! Here is another useful size for doing all sorts of things. Use them as very unique fridge magnets. Fridge magnets that will look the business on that stainless steel fridge. Do science abuse tricks, hold stuff, pick up stuff - all sorts of uses. This is a good size for kids. Well, kids that won't think that they are food anyway. Care still needs to be taken when handling as this size will do a pretty good pinch as well.

Health & Safety

Neodymium magnets are incredibly strong.  It is possible to get a real nasty pinch from two discs as small as D1/2" x 1/8".  Consult your doctor immediately if your child has ingested magnets.  It is also advisable to keep them away from persons wearing electronic medical devices and direct exposure to expectant mothers (better to be safe than sorry).  By all means do not attempt to see if it hurts to put a 1" sphere and a D7/8" x 1" rod magnet on either side of the nose (yes, it did happen and it reportedly really hurts).  Actually he was very lucky they didn't crush his nose - seriously.

Be careful when handling these magnets as they can jump together from fairly long distances.  While it can be entertaining, it can cause this type of magnet to chip if not shatter.  It is not a defect, but an inherent property of the NdFeB alloy.  Neodymium magnets have a typical maximum operating temperature of 80c without losing magnetism.  We do carry a grade (N38SH) which can be subjected to about 176c and can be found in our HiTemp Magnets section.