Festo SIEN-M8B-NS-K-L is an 8 mm diameter inductive proximity sensor — flush mountable, so it sits level with the mounting surface, no air gap needed around the sensing face. 1.5 mm sensing range means it detects ferrous targets at that gap reliably; for a non-ferrous target, expect roughly half that distance. NPN normally-open output, 200 mA max load, 5000 Hz switching frequency — fast enough for counting or position on a moderate-speed conveyor or actuator feedback.
Housing is high alloy steel (sensing face PA), rated IP65/IP67 — sealed against hose-down and temporary immersion, good for washdown zones or damp environments. PUR cable, 2.5 m, stays flexible in cold panels but resists oils and cutting fluids. Operating voltage 10-34 VDC, so it runs on a standard 24 VDC PLC supply without a regulator. Temperature range -5 to 70 °C — fine for most indoor industrial lines, but not freezer storage or oven-side.