This is an addition to K'nex sets that will teach children 12 and up about about mechanical advantage. They can use this add-on set with regular K'nex sets to build small mechanical machines or build a Rube Goldberg machine.

Manufacturing of this toy will be more on the expensive side compared to other small toys. Cheap plastic isn't the best choice, because these parts should be durable enough to be used as actual gears. Metal parts may be too expensive to manufacture, so maybe something like acrylic can be used.

As for safety, these parts present a choking hazard, but the set is meant for ages 12 and up. As long as this doesn't fall into the hands of a young child, this toy is very safe.