What this RCBO is and where it fits
The Siemens 5SU1656-7KK06 is a current-production SENTRON RCBO (residual current circuit breaker with overcurrent protection) that combines a 6 A MCB with C-curve tripping and a Type A residual current device in a single 2-module-wide (36 mm) package, 77 mm deep. It protects a 1P+N circuit — meaning it switches the live pole and monitors the neutral — which is the standard arrangement for single-phase final subcircuits in European distribution boards. The 6 kA breaking capacity per EN 60898 covers domestic and light commercial service; the 25 kA rating per IEC 60947-2 gives you headroom for industrial panel applications where higher prospective fault currents exist.
What the ratings mean on the board
At 30 °C ambient the RCBO carries its full 6 A; at 40 °C it derates to 5.7 A, and at 50 °C to 5.4 A, all the way down to 4.62 A at 70 °C. That derating curve is important if you're packing this into a crowded enclosure where internal temperature runs high — the 6 A label is only good at the reference temperature. Mount it in any position, which helps when retrofitting into an existing board with limited rail orientation. The IP20 rating applies once the distribution board is installed with conductors connected; the front face is touch-safe but the terminals need enclosure protection.