This part is a kind of semiconductor called BES-516-356-xx.

Function of this product has Inductive Sensors.

Manufacturers : Balluff

Image and pinout :

Some of the text within the PDF file :

DC 3-/4- Wire M12×1 non-flush 4 mm 0...3.2 mm M12×1 non-flush 4 mm 0...3.2 mm M12×1 non-flush 4 mm 0...3.2 mm Inductive Sensors M12×1 non-flush 4 mm 0...3.2 mm M12x1 5 DC 3-/4-Wire M12 sn 4 mm M12×1 non-flush 4 mm 0...3.2 mm M12x1 5 Inductive 34.5 35.5 34.5 17 17 LED LED 35.5 M8x1 35.5 Contents 1 Selection Charts Part Numbers Featured GlobalProx® – DC 3-Wire – DC 2-Wire SteelFace® – 2x – 3x – Fe/NFe Welding – Factor 1 – Weld Field Immune – SlagMaster® – Welding Accessories Standard DC 3-/4-Wire Tubular DC 3-/4-Wire Block AC 2-Wire Tubular AC/DC 2-Wire Tubular AC/DC 2-Wire Block DC 2-Wire Tubular DC 2-Wire Block Specialty SuperShorties™ Proxinox® High Temp Analog Large Housing Ring Sensor Connectors Extended Temperature BES 516-356-B [ ... ]

BES-516-356-xx PDF Datasheet Download