The Siemens 5SU9106-0DV32 is a combined residual current device and miniature circuit breaker (RCBO) in a single 1+N-pole module. It provides both earth-fault and overcurrent protection in one DIN-rail unit, saving panel space over separate RCD and MCB. The 10 mA residual sensitivity (Type AC, sinusoidal AC fault currents) is sized for personal protection in wet or high-risk areas — think bathrooms, outdoor sockets, or industrial washdown zones. The 70 mm depth (D=70mm) fits standard Siemens distribution boards and most European enclosure cutouts.
For a critical-spare holding on an existing install, this part is straightforward to source. No need to stockpile ahead of a phase-out that hasn't been declared.