Its interrupting capacity is 121 kA at 240 V, 75.6 kA at 415 V and 440 V, 52.5 kA at 500 V, and 11.9 kA at 690 V — numbers that tell you this breaker is built for high-fault locations like main switchboards or large distribution panels where available fault current is substantial. The 400 A rating holds steady up to 50 °C ambient; above that it derates to 392 A at 55 °C, 384 A at 60 °C, 376 A at 65 °C, and 367 A at 70 °C — so if your panel runs hot, you need to account for the drop.
It is a line-protection design (not a motor-protector or a switch-disconnector), so it is intended for feeder and main breaker duty in distribution panels.