These dice are lightly loaded They roll more naturally than the lead loaded dice, but don’t roll the desired number so often. Because they contain an iron insert, they can additionally be influenced by a magnet.
A precisely shaped iron weight is hidden 1mm below the surface. These dice are both loaded AND affected by a magnet! Iron isn’t as heavy as lead so they’re not as biassed as the lead-weighted ones. The attraction between iron and a magnet isn’t as strong as the attraction between two magnets, so they can’t be controlled over as long a distance. However the two effects taken together make them very versatile in game play. The iron weights increase the probability of rolling the desired number, and the operator has the option of occasionally applying a secret magnet when required! An additional benefit is that the dice themselves are non-magnetic, therefore more than one can be used in the same situation without risk of them being attracted to each other.