Omron's E2A-S08KS02-M1-C2 is an M8 shielded inductive proximity sensor with an NPN normally-closed output, rated for 12 to 24 VDC supply. Sensing distance is 2 mm, housed in a stainless steel barrel 43 mm long with a 27 mm threaded section. The M12 4-pin connector mates to standard quick-disconnect cables. It's a current-production part in the E2A extended-range series, which offers up to 2x the sensing range of standard M8 sensors.
Mounts via an 8 mm through-hole bracket or M8x1 threaded hole. The shielded design allows flush mounting in metal without derating the sensing distance. NPN output is sinking type — verify that the PLC or relay input is configured for sourcing.