The SICK WL23-F430 is a photoelectric sensor with a visible red LED light source, adjustable via potentiometer for light/dark switching. It covers a sensing range from 0.01 m to 9 m, with a response time under 2.5 ms. The PNP switching output and 10–30 V DC supply make it a straightforward drop-in for 24 V control systems. The M12 4-pin male connector means you can swap it without opening the panel — handy when the line is down and you're working off the van.
Rated IP65, so it handles washdown splashes and dusty environments on conveyor lines or packaging machines. The -40 to +60 °C operating range covers cold storage and hot plant floors. Power consumption is ≤ 25 mA, light on the 24 V supply.