The Siemens 3RH1131-1AP00-ZW98 is a SIRIUS auxiliary contactor — a 4-pole switching block used to extend the control-circuit contacts of a main contactor or to build interlocking and signalling logic in a motor control centre. The 6 kV rated surge voltage resistance means it can withstand transient spikes on the line without degrading, which matters when the contactor shares a panel with drives or switching power supplies.
Fastens via screw or snap-on mounting onto a DIN rail — the size S00 footprint (45 mm wide, 57.5 mm high, 72 mm deep) fits the standard panel grid. Wiring accepts solid conductors: 2x 0.5 to 1.5 mm², 2x 0.75 to 2.5 mm², or 2x 4 mm² — enough for control-circuit runs without needing a ferrule for the larger sizes.