The 63 A rating holds from 40 °C up to 50 °C ambient, then derates to 62 A at 55 °C, 61 A at 60 °C, 60 A at 65 °C, and 58 A at 70 °C — so if your panel runs hot, you lose headroom above 50 °C. Breaking capacity runs 121 kA at 240 V AC, 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V, which covers most industrial service-entrance and feeder applications where high fault current is expected.
Dimensions are 70 mm deep, 101.6 mm wide, and 130 mm tall — that's 2.76 in by 4 in by 5.12 in.