It carries a 50 A continuous current at 40 °C and delivers a 121 kA interrupting capacity at 240 VAC — that's the number that governs fault clearing on a 240 V delta or wye secondary, not the higher-voltage ratings.
The interrupting rating drops as voltage climbs: 75.6 kA at 415 V, 52.5 kA at 440 V, and 11.9 kA at both 500 V and 690 V. The 800 V rated insulation voltage (Ui) means the internal clearances and creepage are sized for 800 V class, so the breaker is electrically comfortable on 480/277 V or 600 V systems even though the interrupting performance is published at 690 V.
Above that it derates: 49 A at 55 °C, 48 A at 60 °C, 46 A at 65 °C, and 45 A at 70 °C. Dimensions are 130 mm high, 76.2 mm wide (3 inches — standard MCCB footprint), and 70 mm deep. That 70 mm depth is shallower than some older SENTRON frames, so verify the mounting base depth if retrofitting into a legacy panel with deep bus bars.