It carries a 100 A continuous rating at 40 °C across all three poles, with a 220 kA interrupting capacity at 240 V AC — that figure drops to 154 kA at 415 V and 121 kA at 440 V, so the voltage level on your bus determines the fault current this breaker can safely clear without upstream coordination issues.
Above that, the breaker derates: 98 A at 55 °C, 96 A at 60 °C, 94 A at 65 °C, and 91 A at 70 °C. That heat has to exit the enclosure; in a sealed stainless steel panel with no fan, check the internal temperature rise against the derating curve above.
That width is three 25.4 mm pole spaces — standard for a 3-pole MCCB on DIN rail or direct panel mount.