What the ratings mean for fit
The 3RH1911-1MA20-ZW95: The 2NO contact configuration gives you two independent normally-open auxiliary contacts that close when the main contactor or relay picks up. This is the standard arrangement for signalling the main device's status back to a PLC input, or for interlocking a second contactor in a reversing or star-delta starter. The screw connection from below matches the wiring convention on most S00 contactor assemblies, where the auxiliary block stacks on top of the main device and the line-side wiring enters from underneath. If your panel uses cage-clamp or spring-cage terminals on the main contactor, this block's screw terminals mean a mixed termination style on the same device.
Deployment context
This block clips onto the front of a SIRIUS 3RT2 contactor or 3RH2 contactor relay of size S00. It adds auxiliary contacts without increasing the panel depth beyond the main device's envelope. The DIN EN 50005 mounting profile means it aligns with the standard 45 mm width of the S00 frame, so it fits in the same DIN-rail footprint. For a panel builder, the screw terminals accept solid or stranded copper up to the cross-section the main device's terminals do, and the bottom-entry wiring keeps the auxiliary wiring bundled with the power conductors rather than crossing over the top of the device.