When any beam is broken, the controller signals a stop to the guarded machine. This model is in the F3SG-4RR series, designed for finger detection (14 mm resolution typical for this family), meaning it catches fingers reaching into the hazard zone before they contact moving parts.
What the package tells you
The part ships in a box package — standard for light curtains of this size. No special handling beyond normal ESD precautions for the emitter and receiver heads.