This comprises of a strong U-shaped magnet and a pair of brass rails with 4mm socket terminals. A brass axle with plastic discs is free to roll along the rails and completes the electrical contact between them. When the axle is placed on the rails between the poles of the magnet, and a power supply unit is connected, the axle is repelled and rolls along the rails away from the centre of the magnetic field.

• Dimensions: 175mm x 60mm x 58mm

Requires an external power supply (PP00057620 or similar) and standard 4mm plug leads.