I'm not sure if I just got a bad set, but there are not enough magnets for this to work properly.
There are 4 small magnets around the circumference leaving the top and bottom with no magnet. So if
the magnet has no contact with the cup, it will not hold.
I gave it 2 stars instead of one only
because I will use the balls as a final load for the 'shot glass' chop cup with a gag about
'regulation size' baseball and they are very well made in general.
Should have more magnets.