400 A fixed rating, no derating curve to worry about
That means no derating math when the panel runs hot; the breaker delivers its full ampacity in a warm enclosure. Interrupting capacity is 242 kA at 240 V, dropping to 187 kA at 415 V and 440 V, then 121 kA at 500 V, and 9 kA at 690 V. The 3-pole construction and line-protection design make it a straightforward fit for a feeder or incoming section. It's a bare functional breaker with the shunt trip as the only accessory release.
Panel fit and footprint
Dimensions are 248 mm high by 138 mm wide by 110 mm deep. No surprise on the drill template if you're swapping one in. Power loss is 63.5 W maximum at rated load. That's the heat you need to vent in the enclosure — not trivial, but within what a standard ventilated panel handles for a main breaker of this size.