I admit, I advised grandmother to buy for Christmas this set for Mikolaj. I have some plans for this but more about that soon. 9391 crawler crane is more complex than the truck which we recently built. The final phase of construction made my son ​​a lot of problems but the final effect rewarded his efforts. The vehicle has three knobs which we can:

• rotated head through an angle gear,
• raise the arm by a worm gear,
• leave the hook on a rope

Retractable arm increases the crane range. The second instruction shows how to construct bulldozer.