This can be through balance test of a powerful magnet suction.
Is the first fixed a strong magnet.
Another piece of hanging on the dynamometer.
And put two pieces of shenzhen powerful magnets attract together.
Shenzhen powerful magnet manufacturer will take three 'vertical with the ground, pulling on a dynamometer, read two separate magnet 'moment' to force the dongguan powerful magnets.
If you have to hang on the dynamometer magnet for G.
, calculate the biggest attraction between powerful magnet manufacturer is equal to F - dongguan
Eventually the results is that we want.