The Siemens 3RG7202-6BG00 is a SIMATIC PXO630 K80 thru-beam sensor transmitter. It's the emitter half of a photoelectric pair, sized at 83x61x25 mm, with a DC 10-36V supply, PG11 cable entry, 3-pole connection, and IP67 enclosure.
Thru-beam sensors like this one are used for presence detection across conveyor lines, packaging machinery, and automated material handling. The transmitter and receiver are separate housings; this is the transmitter side. The IP67 rating handles washdown and dusty environments.