It provides four normally-open instantaneous contacts for switching control circuits, signal interlocking, or extending the contact count on a main contactor. Depth is 73 mm, width 45 mm, height 57.5 mm, so it fits the same footprint as other S00 auxiliaries; no need to gut the existing layout if you are swapping in from an earlier SIRIUS generation.
The 3RH2140-1AK20 carries a rated switching current of 10 A at 24 V and also 10 A at 230 V, both at 50/60 Hz. For DC switching the curve is steeper: 4.7 A at 60 V, 1.2 A at 220 V, 0.5 A at 440 V, and 0.26 A at 600 V. The arcing time runs 10 to 15 ms. These are the values that govern whether the contactor holds up under your specific pilot-duty or signal load — match the voltage and current on your coil or indicator circuit against the appropriate row, not the highest number on the datasheet. The contactor is rated for 30 million mechanical operations typical, which for a frequently cycled interposing relay means years of service before the contacts wear.