This combination package of the Pulleys and Gears Sets contains the maximum of parts of the individual respective. Twenty models are introduced, which cover the complete range of Pulley and Gear themes. Along with the 18 basic ENGINO parts included, there are pulleys of 3 different sizes, various types of gears such as crown, worm and rack gears, screws, cams and cranks! The models are scientifically designed to almost cover all the different types of mechanisms. Learn how these machines can help change speed, change the direction of rotation, increase force, transfer force and much more! Detailed instructions for 20 models are included. 37 x 7 x 31 cm. Age: from 7 years