Comprises a set of two transparent plastic plates 153 x 76 x 6 mm, each plate has a matrix of 98 (14 x 7) small circular chambers, each chamber containing an iron rod and functioning effectively as a plotting compass. The plates may be arranged in various ways, e.g. as a single large two dimensional surface, as faces of a cube etc., and in this way may be used to show configuration of a magnetic field in one or two dimensions. The transparent nature of the plates also makes them suitable for use on an overhead projector.

Magnet not included.