The Siemens 5SU9356-1CR06 is a SENTRON RCBO — an RCD-operated circuit breaker combining overcurrent and residual-current protection in a single 2-module-width (36 mm) package.
The 6 A rating at 30 °C derates to 5.64 A at 40 °C, 5.46 A at 45 °C, 5.22 A at 50 °C, and 4.86 A at 55 °C — so in a warm panel (say 45 °C) you're limited to about 5.5 A continuous load. The C-curve trips at 5–10× In, meaning it holds through the start-up surge of a fractional-horsepower pump or a bank of LED drivers but clears a hard fault fast. The 1P+N design switches the line and breaks the neutral, but only the line is protected against overcurrent — the neutral pole is switched only, not monitored. That's standard for single-phase final subcircuits in many European and Asian distribution boards. The IP20 rating applies once the distribution board is installed with connected conductors — fine for a closed panel, not for a wet environment.
At 2 modular units wide (36 mm) and 77 mm deep (70 mm installation depth), it occupies two standard 18 mm DIN-rail slots.