A set for building a bulldozer and 9 other types of construction vehicles The models work without batteries. With over 200 interchangeable components such as flat and conical cogged wheels, racks, differential gears, worm screws, spiked tyres, bars and panels. The bulldozer’s bucket lifts up thanks to a worm gear mechanism and the vehicle changes direction when you turn the steering wheel. The instruction manual helps the children build the models and introduces them to the basic principles of mechanics and engineering. With the free app with 3D interactive instructions, there are lots of other applications to discover and build. Suitable for children from 8 years and older. Made in Italy.