The Schneider Electric A9K24640 is an Acti9 iK60N miniature circuit breaker rated 40 A at 30 °C with a C-curve trip characteristic (magnetic tripping between 5 and 10 x In). It breaks fault currents up to 6000 A Icn at 230 V AC, 50/60 Hz, conforming to EN/IEC 60898-1.
This is a 1P+N configuration — one protected pole, switched neutral on the left, occupying 4 x 9 mm pitches (36 mm wide) on a DIN rail. The clip-on mount and tunnel terminals (accepting up to 35 mm² rigid or 25 mm² flexible) make it a straightforward swap into an existing Acti9 or similar 18 mm-pitch distribution board. Depth is 78.5 mm, height 85 mm — check your enclosure door clearance if you're retrofitting into a shallow gland plate.
Thermal-magnetic trip unit, no earth-leakage protection built in. Mechanical durability is 20,000 cycles, electrical 10,000 cycles — typical for a distribution-grade MCB in a panel that sees occasional switching.