Magnetic View Film Green 4x6"
This listing includes one piece of 4 x 6" magnetic view film which can show you how the magnet are magnetized and the magnetic density distributions.
As advertised, this film allows you to see how a field looks near or on the surface of a magnet. It seems like the most useful application is on the surface of a magnet, seeing the split between the poles. It shows that the line between the poles is fairly distinct (not what I would have expected).