What this 25 A C-curve 2-pole MCB does on the rail
The SENTRON 5SQ2270-0KA25 is a 2-pole miniature circuit breaker rated 25 A with a C tripping characteristic, switching both phase and neutral (neutral conductor switching is built in). It breaks fault currents up to 3 kA under both EN 60898 and IEC 60947-2 — the same 3 kA figure applies to either standard, so you don't need to track two ratings. At 400 V AC, 50 Hz, this is a straight 25 A branch-circuit protector for a 2-pole load.
Two width units (about 36 mm on a standard DIN rail), 55 mm installation depth. Overvoltage category 3 and energy limiting class 3 mean it's designed for fixed-installation distribution boards, not portable equipment. The 2-pole form factor with switched neutral matches European-style single-phase sub-circuits where you want to isolate both conductors.