This is a VERY misleading way to describe a magnet’s capability and unfortunately used all to often to embellish the potential of the magnet. Technically, magnets are measured in “Gauss” strength which is a scientific way of measuring, using a gauss meter, the strength at the surface and at various distances away from the magnet. It is the only accurate and correct way to determine magnetic strength. The question of lifting power on flat steel plates at various distances is only possible in controlled environments, a situation which is certainly not replicated when in actual use. All applications vary, it is best to describe your application to us so we can make the proper suggestion on which magnet will work best