Definitely not toys. These things are strong and will pinch if mishandled. They have an incredible amount of holding power and are a great choice for firmly attaching metal objects to each other. Only purchase these if you are very familiar with neodymium magnets and can handle large ones safely.
These blocks are often used for water conditioning and making fuel saving devices.
Also available in this size: BX0X06-N52
(Grade N52) and BX0X06TP-N52
(Grade N52, Black rubber coated)