Electric Motor Add-on
The motor kit comes with a pre-assembled and tested motor and battery holder, a motor mounting bracket, a coupler (which replaces the hand-crank on most of the models), and all the nuts and bolts needed to attach the motor and battery holder to one of the compatible kits.
You can see that the motor is very small: this is a good thing! It is small, quiet, and not strong enough to hurt anyone. If you stick your finger into the gears when one of the models is running, the motor just stops without hurting your finger or the model.
Four AAA batteries are included!