It shows the signals used by crane rigger, in addition to knowing the safety systems and preventive measures against tipping and electrical risk to use in the cranes.

Within the signs shown we have:

Use the main hook
Use the auxiliary hook
Climb or hoist
Go down
Lift the pen
Download the pen
Raise the boom and lower the load
Lower the boom and lift the load
Turn
Extend the boom (telescopic booms)
Retract the boom (telescopic booms)
Extending the pen
Retract the pen
Move slowly
Stop
Emergency stop
Displacement (a caterpillar)
Displacement (both caterpillars)
Displacement
Secure everything