When any opaque object (a hand, a forearm, a tool) breaks one or more of the synchronized beams, the controller sends a stop signal to the machine safety circuit. This particular unit provides a 1985 mm protected height, sized for guarding a full body-height opening on a machine cell or conveyor entry point. The F3SJ series uses a synchronized emitter-receiver pair with a slim housing profile, designed for mounting on machine frames or stand-alone posts. The 1985 mm height covers the reach zone for standing operators — a typical point-of-operation or perimeter guard application where a person could reach into a hazard. The P25 suffix indicates a 25 mm resolution, meaning it detects fingers and small hand tools passing through the field.
Packaged in bulk — no retail box, just the unit with its mounting brackets and documentation. That is the standard delivery format for panel-build quantities. If you need a single unit for a critical spare cabinet, bulk is fine; just plan to store it in a clean, dry location with the protective end-caps on the optical windows.
The 1985 mm protected height determines the physical span of the guarded opening. For a machine access gate or a conveyor infeed, the emitter and receiver columns must be mounted such that the optical field covers the full height an operator could reach through. The 25 mm resolution (P25) classifies this as finger-protection level per IEC 61496-2 — the beam spacing is tight enough that a finger entering the field breaks at least one beam before reaching the hazard. Bulk packaging means the light curtain ships as a single assembly with its two columns (emitter and receiver), plus the mounting brackets and alignment tool. No separate controller module is included — the F3SJ series integrates the control logic into the receiver head, so it connects directly to the machine safety relay or safety PLC via the standard OSSD outputs. Verify the cable length and connector type on your specific variant before panel wiring.