It carries 4 normally-open instantaneous contacts, meaning all four close together when the coil picks up, with no make-before-break or delayed switching in the path. The contacts are rated for 10 A at 24 V, stepping down to 6 A at 230 V and 3 A at 400 V, so the thermal capacity follows the expected derating curve for a size S00 block. The S00 frame size tells you it mates physically with the S00 contactor range — same footprint, same rail slot.
The 4 NO contact arrangement is the most common auxiliary block for signalling 'contactor closed' back to a PLC or for interlocking a second device. Because there are no NC contacts built in, you need a separate block if your circuit requires a normally-closed feedback path. Contact reliability is specified as one incorrect switching operation per 100 million cycles at 17 V, 1 mA — that is the dry-circuit reliability figure. If you are switching low-energy signals (PLC inputs, sensor power), this block will not give you intermittent opens. The mechanical endurance of 30 million operations means it outlasts most main contactors it will be paired with.