It carries dual ratings: 10 kA breaking capacity per IEC/EN 60898-1 and 20 kA per IEC 60947-2, with a UL 1077 listing at 5 kA for North American acceptance.
For DC circuits, it's rated 15 kA at up to 72 V, so it works in 48 V or 60 V control-power loops. The 440 V AC multi-phase rating means it can be used on 400 V three-phase systems (line-to-line) without derating the voltage.
Where it goes in the panel
The 18 mm width (1 modular unit) keeps the footprint tight. The IP20 rating (with conductors connected) is standard for enclosed gear; it's not meant for washdown zones or outdoors without a cabinet.