The Siemens 5SL6406-6RC is a 4-pole miniature circuit breaker rated 6 A with a B tripping characteristic and 7.5 kA breaking capacity. The 7.5 kA breaking capacity tells you the MCB can safely interrupt a fault current up to that level at the rated voltage; in a domestic or light commercial distribution board with a typical prospective short-circuit current under 6 kA, it has headroom to clear a bolted fault without welding its contacts shut.
RoHS compliant since 2014-08-05. REACH Article 33 duty applies — lead (CAS 7439-92-1) is present above 0.1% w/w in the product. Export control classification is AL:N / ECCN:N, meaning no special license is required for standard cross-border shipments.