Coloured ring magnets which if placed on the rod supplied and orientated so that they mutually repel will ';float' one above the other. These can be used in demonstrations to show how magnets attract and repel.Magnet size:Outer diameter: 30mmInner diameter: 12mmThickness: 9.8mmPack size: 5 WARNING! 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.