The WTB11-2N2431 is a photoelectric sensor with an NPN output manufactured by the company Sick. It has a sensing range of 20 to 350 millimeters, and it is a Dark-ON / Light-ON type. It provides reliable non-contact sensing even in difficult sensing conditions,Features include fast switching, mounting versatility, high noise immunity, and large operating temperature range. It is suitable for a variety of industrial applications including sorting, positioning, counting, and others.