The Siemens 5SU1653-0KV25 is a combined RCD/MCB — an FI/LS-Protector Type AC (WS) — in a 1+N-POL configuration with a B-curve 25A overcurrent trip and a 300mA residual current sensitivity. Rated breaking capacity is 4.5kA. The 70mm width (D=70mm) means it takes up two standard modular DIN-rail slots in a consumer unit or distribution board.
The Type AC designation means it detects sinusoidal AC residual currents only — standard for general-purpose socket circuits and lighting in residential or light commercial panels. The 300mA sensitivity is a fire-protection level, not personnel protection (30mA would be required for that). The B-curve 25A trips between 3 and 5 times rated current, suited for resistive and small inductive loads.