The 25 A rated current (In) and C-curve mean the thermal-magnetic trip holds for general-purpose loads like socket outlets and small lighting circuits, but the magnetic threshold at 5 to 10 x In (125 to 250 A instantaneous) is deliberately higher than a B-curve — so it avoids nuisance trips on moderate inrush from small motors or capacitive loads, yet still clears a hard fault fast. Breaking capacity is 6 kA Icn at 230...240 V AC, 50 Hz, per EN/IEC 61009-2-1. That is the standard domestic and light-commercial fault level in most European installations; if your prospective short-circuit current at the board exceeds 6 kA, you need an upstream current-limiting device or a higher-rated RCBO. The 300 mA residual sensitivity is intended for protection against fire risk from persistent earth faults, not personal shock protection.
Clip-on mounting to DIN rail, 4 modules wide at 9 mm pitch (36 mm total). The neutral is on the left, phase on the right — fixed polarity, so check the busbar arrangement before wiring. Terminals accept 1 to 16 mm² rigid or 1 to 10 mm² flexible; strip 15 mm and torque to 2 N·m. The toggle gives clear ON/OFF/trip indication.