The A9F04703 is a 3 A, 3P+N miniature circuit breaker from the Schneider Electric Acti9 iC60N series. At 440 V AC the Icu drops to 25 kA, so if your line-to-line fault current exceeds that, you need a higher-rated upstream device. The thermal-magnetic trip unit gives you both overload protection (thermal bimetal, slow response) and short-circuit protection (magnetic solenoid, instantaneous). Overvoltage category IV means it's rated for the main distribution board — not just sub-panels.
The 3P+N footprint takes 8 x 9 mm pitches = 72 mm width, so it occupies four modular spaces on the rail. Height is 91 mm, depth 78.5 mm — fits standard distribution enclosures with a 100 mm minimum internal depth. IP20 finger-safe terminals, so no additional shrouding needed inside a locked panel.