Fotek proximity sensors are an economical, widely stocked choice for detecting metal parts on machines, conveyors and packaging lines. The PM series covers cylindrical threaded housings from M5 to M30; the PS series is a square block that mounts flat with two screws.
The code tells you everything: PM18-08N is an M18 sensor with 8 mm sensing distance and NPN normally-open output; P is PNP, NB/PB the normally-closed versions, -M12 a connector version and PM18E an extended-range type. In the PS series, PS-10N is a square sensor with 10 mm range and NPN output.
Match the output type (NPN or PNP) to your PLC inputs when replacing a sensor. Send the code from the old sensor and we supply the same type.