The Siemens 3RG4013-0KB00 is an inductive proximity switch in a standard M18 x 69 mm barrel housing with a cable connection. It senses ferrous targets at a rated operating distance of 5 mm, with an assured operating distance of 4.05 mm and an effective range of 4.5 to 5.5 mm against an 18 x 18 x 1 mm mild steel target. Rated for 230 V AC/DC and 300 mA, it handles both AC and DC control circuits without needing a separate supply selector.
The M18 barrel mounts through a standard 18 mm hole in a bracket or machine frame. The cable exit means no separate connector is needed — just route the cable back to the control cabinet or junction box.