The A9F05240 is a 2-pole miniature circuit-breaker from the Acti9 iC60N series, rated 40 A with a D tripping curve. The 36 kA Icu at 12-133 V AC is the maximum short-circuit current the breaker can safely interrupt at that voltage range; at 400 V AC the breaking capacity drops to 10 kA Icu (and 10 kA Icn per EN/IEC 60898-1), so verify the available fault current at the installation point. The part is certified to both EN/IEC 60947-2 (industrial) and EN/IEC 60898-1 (domestic/installation), meaning it's accepted in distribution panels and industrial switchgear alike. Overvoltage category IV and pollution degree 3 suit it for main distribution boards and harsh environments.
Snaps onto a DIN rail (mounting support per the spec), occupies 4 x 9 mm pitches = 36 mm width, 91 mm height, 78.5 mm depth. The double terminal accepts 1-35 mm² rigid or 1-25 mm² flexible on top or bottom; wire stripping length is 14 mm, tightening torque 3.5 N.m. The toggle control and trip indicator give local status without removing the cover.