• Every action has an equal but opposite reaction-right before your very eyes.
• Science Balance Ball demonstrated clearly and simply and with a touch of a amusement.
• Material: 5 steel balls, ABS plastic frames and base.
• Weight: 240g
• Dimension: 135*135*115mm

Note:

• If you pull up one ball and release, you will see only one ball move from that reaction.
• If you pull up two Toys balls, two balls will react.
• Notice: the balls do not swing indefinitely and eventually stop. This size keeps longest swing time.
• This product is not intended for children under 12 yrs.