The Siemens 3RH1911-1HA01-ZW97 is a SIRIUS auxiliary switch block designed for use with contactor relays and power contactors. Rated 10 A at 24 V (AC-12), the switching capacity drops with voltage: 6 A at 24 V DC, 3 A at 110 V, 1.2 A at 220 V, and 0.26 A at 600 V — the load curve you need to match against your control circuit's voltage and current draw.
Dimensions are 36.5 mm wide, 41.5 mm deep, and 37.5 mm tall — fits the standard contactor footprint. Screw-type terminals accept 2x (0.5 to 1.5 mm²) or 2x (0.75 to 2.5 mm²) with core end processing, or 2x (20 to 16) and 2x (18 to 14) AWG.