The Siemens 3RG7401-7GB00 is a SIMATIC PXO320 K21 retro reflective sensor with an integrated polarisation filter, housed in a 31x20x12 mm package. It operates on DC 10-30V, provides a 3 m sensing range, and switches NPN light-on at up to 150 mA. Connection is via an M8 3-pole connector, and the enclosure is rated IP68.
The 3 m range with polarisation filter lets it see through shiny or reflective targets that would fool a standard retro sensor — useful on glossy packaging or metal cans. The NPN light-on output is common for PLC inputs that sink current; verify your controller's input type before wiring. IP68 means it survives washdown environments, but the M8 connector must be mated with an IP68-rated cordset to maintain the seal.