The Siemens 3RG46 02-1AB00 is an inductive proximity sensor in a 6.5 mm diameter cylindrical nickel-plated brass housing. It detects ferrous targets at 3 mm and switches a PNP normally-open output at up to 200 mA — suited for position sensing on small actuators or valve position feedback in a control panel.
This sensor shares the same electrical design and sensing range as the alternate MPN 3RG46021AB00, which is listed as a used-condition variant. Both are PNP, normally open, 3 mm range, and fit the same 6.5 mm mounting hole — no rewiring needed for a swap.