It's an instantaneous design (no intentional delay), so it clears ground faults as fast as the waveform allows, which matters when you're coordinating downstream with a selective main RCCB or an upstream MCB that needs to hold through a transient.
Type A detection means it catches sinusoidal AC residual currents plus pulsed DC (typical from single-phase rectifiers, switched-mode supplies, or variable-speed drives). Rated short-circuit current withstand is 10 kA per IEC 61008-1 and EN 60898; the let-through energy is capped at 58 000 A²·s. Surge-current resistance is 1 kA (8/20 µs wave), which helps it ride through lightning-induced transients without nuisance tripping.
The 25 A rating holds across the full ambient range from -25 °C to 55 °C without derating; at 65 °C it derates to 23.3 A, and at 70 °C to 17.6 A. Storage limits are -40 °C to 75 °C. Overvoltage category III — suitable for fixed-installation distribution boards downstream of the utility meter.