The Siemens 5SU9106-1DV20 is a combined line-surge and residual-current protective device (LS/DI) — a single-module RCBO that integrates overcurrent protection and earth-leakage detection in a 1+N-pole form factor.
The 10 mA residual sensitivity (IΔn) is the key differentiator here. Standard RCBOs for general building circuits are 30 mA; a 10 mA device is specified where the fault path must be interrupted at a much lower leakage to prevent ventricular fibrillation in sensitive environments (IEC 60364-7-710 for medical locations, for example). The 1 MW marking on the description likely references the insulation monitoring capability or the maximum system voltage; in any case, this unit is designed for single-phase final circuits up to 20 A.
This is a DIN-rail mounted device, 1+N-pole width (two modules wide on a standard 35 mm rail). The D=70 mm dimension refers to the depth from the mounting surface to the front of the device — check enclosure depth if retrofitting into a shallow panel. The 1+N-pole busbar arrangement is standard for single-phase RCBOs; verify your distribution board's busbar pitch and neutral-bar take-off before installing.