The Schneider Electric A9D54216 is an Acti9 iC60 RCBO — a combined thermal-magnetic circuit breaker and residual-current device in a single 36 mm wide, 2-pole module that clips onto a DIN rail. The 10 kA Icn breaking capacity at 230 V AC per EN/IEC 61009-2-1 (15 kA Icu per EN/IEC 60947-2) tells you it can safely interrupt a bolted fault up to that level on a 50 Hz network — enough for most distribution outgoing circuits in a panel. Integrated earth-leakage protection at 300 mA sensitivity covers the outgoing circuit against ground faults — typical for distribution sub-circuits where a 30 mA trip would be too sensitive for leakage from long cable runs or equipment. The thermal-magnetic trip unit handles overload and short-circuit; the residual-current element handles ground faults. Local signalling on the toggle shows ON, OFF, and fault-trip status, which helps a field technician isolate a tripped circuit without needing a meter first.
IP40 in a distribution enclosure (IP20 bare) is typical for indoor panel use — not rated for washdown, so keep it inside the cabinet.