It belongs to the F3SJ series of safety light curtains, designed to protect personnel from reaching into pinch points, press brakes, robotic cells, and other automated hazards.
What the safety light curtain class does
Safety light curtains like this one replace physical barriers (gates, guards) with an optical detection field. When an object — typically a hand or finger — breaks the beam pattern, the curtain sends a stop signal to the machine's safety controller. They are rated per IEC 61496 for Type 4 (highest safety integrity) or Type 2 (basic), depending on the variant, and are used to safeguard access to hazardous zones while still allowing material flow through the guarded opening.