It's a 3-pole unit with a continuous current rating of 800 A at 40 °C — that's the number you spec for the bus or cable it's protecting. The breaker carries a shunt trip release (STL) factory-installed — that's your remote trip coil for emergency-stop or fire-alarm integration. The basic switch assembly inside is order code 3VA15805EF320AA0, which is the replaceable switching mechanism.
At 55 °C it drops to 780 A, at 60 °C to 761 A, and at 70 °C to 722 A. If your panel is sitting next to a hot motor or a furnace, that derating curve tells you whether the breaker will hold its full load without nuisance tripping. The interrupting capacity is also given at several voltages: 187 kA at 240 V, 121 kA at 415 V and 440 V, 75.6 kA at 500 V, and 52.5 kA at 690 V. That's useful for selectivity studies — you can coordinate downstream breakers knowing the upstream device can handle the full fault current. Dimensions: 320 mm height, 210 mm width, 120 mm depth. That depth is the panel depth you need behind the door — 120 mm (4.72 in) — which is standard for this frame size.