Coloured ring magnets which, if placed on the rod supplied and orientated so that they mutually repel, will float one above the other. Magnet size: Outer diameter: 30mm. Inner diameter: 12mm. Thickness: 9.8mm.Pack size: 5WARNING! Not Suitable for Children under 3 years due to small parts. This product contains magnets or magnetic components. Magnets can cause serious or fatal injury if swallowed.