The 30 MODELS set is the middle size package of the enginnering series and is ideal for both beginners and itermediate users. It contains enough parts to build faily large and functional models and also includes the engino 3V geared motor for some amazing contraptions! The featured motorized pterosaur is using a crank to convert rotational motion to reciprocating, moving the wings up and down creating a flapping effect. The other models inlcude a tow-truck, a motorbike with turning wheels, cranes etc (one at a time). Printed instructions are included for 7 models while the others can be dowloaded from the engino´s website. The package is suitable for 6-14+ year old builders.