The Schneider Electric A9KF71220BQ is a 20 A, C-curve, 2-pole miniature circuit breaker from the Acti9 K60 series, built for distribution boards and final-subcircuit protection on AC networks at 50/60 Hz.
Rated 20 A continuous, this breaker protects a circuit sized for that load — think a 20 A lighting distribution board, a small HVAC fan coil, or a bank of office sockets. The 10 kA Icn breaking capacity at 415 V AC (EN/IEC 60898-1) tells you it can safely interrupt a fault current up to 10,000 A at that voltage, which covers most commercial and light-industrial installations where the prospective short-circuit current at the board is under that threshold. If your site's fault level exceeds 10 kA, you need a higher-rated device upstream or a current-limiting MCB. The 2-pole construction (2P) switches both line and neutral on a single-phase supply, or one pole per phase on a two-phase circuit. Thermal-magnetic trip technology means it responds to both sustained overloads (thermal bimetal) and short-circuit faults (magnetic coil) — no electronics to fail, no auxiliary power needed.
IP20 finger-safe terminals are fine inside a closed panel; no washdown rating here, so keep it dry.