The Schneider Electric A9P64310 is an Acti9 iC40N miniature circuit breaker (MCB) with a 10 A rated current, D tripping curve, and 3-pole configuration. The D curve means the magnetic trip operates at 10 to 14 times the rated current (10...14 x In per EN/IEC 60898-1, 12 x In ±20% per EN/IEC 60947-2). Breaking capacity is 10 kA Icu at 400 V AC per EN/IEC 60947-2, with a lower 6 kA Icn rating under EN/IEC 60898-1. The dual standard certification means it's accepted for both industrial (60947-2) and domestic (60898-1) installations — useful when the same panel feeds mixed loads.
The 3-pole body occupies 6 module pitches (9 mm each, so 54 mm total width) on a DIN rail. Depth is 74 mm, height 85 mm. That's a standard footprint — it slots into any Acti9 distribution board without crowding the adjacent devices. The tunnel-type terminals are the same top and bottom, so you can feed through or loop without re-terminating. IP20 on the body, IP40 inside a modular enclosure. Fine for most indoor panels; if you're in a dusty or humid environment, make sure the enclosure seals properly.