The boom extends the same as the other sets with this boom; simply pull it. It works surprisingly well and due to circular ridges inside the boom the extension (which is just a standard beam) will hold in place.
The gear at the back controls the height of the boom.
As you can see the boom is only half extended.
Boom fully extended, half down.
The cable is kept in place via two gears and a blue pin, same as the 7905 crane. Even under decent weights this works well.
The stabilisers however cannot handle much weight once the load is moved off axis.
The stablilsers are a very simple but effective design.
Another shot of the stablilsers. This also shows how far the boom will decend.
The boom height mechanism works well also. I love the cab design.
Overall this is a remarkable achievement for the low price. I bought it for the boom piece as I want to improve the crane that came with