The Siemens SENTRON 5SU1656-1KK06 is a 2-pole (1P+N) RCBO — a combined residual-current circuit breaker with overcurrent protection, in a 36 mm wide (2 MW) housing.
This derates as temperature climbs — at 40 °C it's 5.7 A, at 50 °C it's 5.4 A, and at 70 °C it drops to 4.62 A. The C-curve (tripping characteristic class C) means magnetic trip occurs at 5–10 times rated current — 30–60 A for this 6 A unit. That's the standard choice for general-purpose distribution with motor or capacitive loads. The energy limitation class is 3, which keeps let-through energy low enough to protect downstream wiring and connected equipment.
Where it goes in the panel
The housing is IP20 rated only when the distribution board is installed and conductors are connected, so it's not for open-panel or washdown environments.