It's a 3-pole unit rated for 50 A continuous current at 40 °C, and it holds that same 50 A rating all the way up to 50 °C before it starts to derate. That thermal curve matters: at 55 °C it's still good for 48 A, at 70 °C it's 45 A, so you get full nameplate capacity in most ventilated enclosures without having to oversize.
This breaker carries a 187 kA interrupting rating at 240 V, 121 kA at 415 V, 75.6 kA at 440 V, and 17 kA at 690 V. Those are high-end figures for a 50 A frame — it'll clear a bolted fault on a large transformer secondary without the arc flash escalating.