It protects a single-phase final subcircuit (1P+N) at 4 A rated current, B curve, with integrated 300 mA earth-leakage protection. Breaking capacity is 6 kA Icn at 230/240 V AC, 50 Hz, per EN/IEC 61009-2-1.
The 4 A rating and B curve (magnetic trip at 3–5× In, so 12–20 A) make this unit suited for lighting circuits or small resistive loads where inrush is low. The integrated 300 mA residual-current element is a delayed or S-type characteristic by default — it's intended for fire protection or circuits where a 30 mA RCD would nuisance-trip (e.g. fixed equipment with natural leakage). Not for socket-outlet circuits requiring 30 mA personal protection. Neutral is on the left, phase on the right.
The 36 mm width and clip-on DIN rail mount mean it snaps directly into a standard distribution board alongside other Acti9 or third-party modular devices. The toggle indicates ON, OFF, and fault-trip status locally.