The Schneider Electric A9R82291 is a 2-pole residual current circuit breaker (RCCB) from the Acti9 iID series, rated 100 A with 300 mA earth-leakage sensitivity. It's a Type AC, voltage-independent device — meaning the trip mechanism draws its energy from the fault current itself, not from a separate power supply, so it remains functional even if the line voltage drops. This makes it a straightforward choice for general-purpose protection on single-phase outgoing circuits in distribution boards.
The 100 A rated current (In) and 300 mA sensitivity cover most residential and light commercial sub-mains or feeder circuits where the load is resistive or lightly inductive — think water heaters, oven circuits, or general socket outlets. The 1500 A rated breaking capacity (Idm/Im) is adequate for downstream fault clearing in a typical TN or TT system, but if your fault current at the installation point exceeds that, you'll need an upstream MCB or fuse to coordinate.
The neutral is on the left, which matters for busbar alignment in a standard Acti9 distribution board.