What it is and what it fits
The 3RH1911-1FB11-ZW97 is an auxiliary switch block from Siemens, configured as 1 normally-open plus 1 normally-closed contact (1NO+1NC), with screw terminals. It is designed to mount on Size S00 contactors and contactor relays, following the DIN EN50005 mounting standard. The multiunit packing ships 140 pieces per carton, which is the unit of issue for this order code.
What the contacts mean for the circuit
The 1NO+1NC contact arrangement gives you one make and one break contact in a single block. On a Size S00 contactor or relay, this block clips onto the front, adding auxiliary signalling or interlocking without increasing the panel footprint. The screw terminals are rated for the standard control-circuit currents you would expect on S00 gear — suitable for PLC inputs, status lamps, or holding-circuit interlocks in a motor starter. Because it follows DIN EN50005, the terminal numbering and contact sequence match the conventional European scheme, so a panel builder or commissioning engineer can wire it without cross-referencing a separate drawing.