The Siemens 3RG7401-0HH61 is a SIMATIC PXO320 K20 retro-reflective photoelectric sensor with a polarization filter, sized for tight spaces at 31x20x12 mm. It runs on 10-30 VDC, switches NPN output up to 100 mA, and covers a 3.5 m sensing range. Light/dark-on is programmable via the cable, and the 2 m PUR pigtail (4x0.14 mm²) keeps IP67 intact for washdown zones.
Mounts via the 31x20 mm face; the 12 mm depth fits behind thin guards or in compact conveyor-side brackets. The polarization filter rejects false triggers from shiny targets — useful on wrapped pallets or glossy packaging. Program the output action (light-on or dark-on) by connecting the programming line per the manual; no separate teach-in tool needed.