Bee Magnets with Key?

The magnets need to be a bit stronger.  Attached a key (.2 oz) and it just holds on a dry erase board.  But only on one side of the magnet.  The other side slips down the dry erase board. By using the hexagon magnet with the weaker magnet side, the key weight will hold.  But again, it just holds.  The next version will update the neodymium magnets from 2mmx6mm to 3mmx6mm.