The thermal derating curve is published: it holds 400 A through 50 °C, drops to 375 A at 55 °C, and steps down to 300 A at 70 °C, so if your enclosure runs hot, size the breaker for the actual ambient, not the nameplate. Breaking capacity is voltage-dependent: 242 kA at 240 V, 187 kA at 415 V and 440 V, 121 kA at 500 V, and 7.5 kA at 690 V. At 690 V the 7.5 kA figure means this breaker is not your first choice for 690 V distribution unless the available fault current is known to be low. Communication function is present, which means it can talk to a higher-level system for metering or remote status.
Physical envelope: 110 mm deep, 138 mm wide, 248 mm tall. Verify the cutout and bus-bar spacing against your existing panel layout before ordering.