The Siemens SENTRON 5SL6401-7 is a 4-pole miniature circuit breaker rated 1 A with a C tripping characteristic, breaking 6 kA at 400 V AC per IEC/EN 60898 and IEC 60947-2. This is the part for a 4-wire single-phase or three-phase plus neutral final subcircuit where you need thermal-magnetic protection on all poles and the load draws under 1 A — think control transformers, lighting contactor coils, or small power supplies in a residential or light-commercial distribution board.
IP20 with connected conductors — finger-safe once wired, but not for wet environments.
At 1 A, this is a low-current pole; verify the downstream load's full-load amps don't exceed 80% of the breaker rating for continuous duty per NEC/EN 61439 derating rules.