The SM31RQD is a mini-beam photoelectric sensor receiver from Banner Engineering's Mini-Beam Series, featuring a 3-meter detection range. It operates with a 10-30 VDC input and provides bipolar output with 1 NPN and 1 PNP configurations. The sensor comes with an M12 4-pin connector, integral quick disconnect (QD), and IP67 enclosure protection for durability in industrial environments.