What this MCB does and where it fits
The Siemens SENTRON 5SL6225-8CC is a 2-pole miniature circuit breaker with a D tripping characteristic, rated 25 A at 400 V AC and a 6 kA breaking capacity per EN 60898. It occupies 2 modular width units (36 mm) on a DIN rail, with an installation depth of 70 mm and overall depth of 76 mm, so it fits standard residential and light-commercial distribution boards.
Breaking capacity of 6 kA at 400 V AC per EN 60898 — this is the standard residential/infrastructure rating; verify the prospective short-circuit current at the installation point doesn't exceed this. The D-curve trips magnetically between 10× and 20× In (250–500 A), so it's sized for loads with a high starting surge, not for general-purpose socket circuits where a B or C curve would be more selective.