The 100 A rating holds flat from 40 °C to 50 °C, then derates to 98 A at 55 °C, 96 A at 60 °C, 94 A at 65 °C, and 91 A at 70 °C — so in a warm panel you lose about 9 % at the top of the operating range. The interrupting capacity is 187 kA at 240 V, 121 kA at 415 V, 76 kA at 440 V, and 17 kA at 500 V and 690 V; that 187 kA at 240 V is the headline number for high-fault commercial services. It is a line-protection device (not a motor-protection curve), so it is sized for feeder or distribution duty, not for starting inrush.
The breaker measures 70 mm deep by 101.6 mm wide by 130 mm high. It is a standard panel-mount MCCB — no DIN-rail clip, so it bolts into a cutout or mounts on a backplate with the supplied hardware. The 4-pole footprint is wider than a 3-pole unit, so check the gland-plate space if you are retrofitting into an existing distribution board.