That means you're not locked into a fixed thermal-magnetic response — you can dial in the trip characteristics to coordinate with downstream breakers and protect branch circuits without nuisance trips.
The interrupting ratings on this breaker are serious: 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 3.4 kA at 690 V. The drop to 3.4 kA at 690 V tells you it's optimized for the 240–500 V range; at 690 V you need to verify your fault current stays under that ceiling.
Thermal derating — the real continuous current in your environment
This breaker is rated at 63 A continuous from 40 °C up through 50 °C ambient. That's your baseline. At 55 °C it derates to 60.6375 A, at 60 °C to 58.275 A, at 65 °C to 55.9125 A, and at 70 °C to 53.55 A. If you're stuffing this into a crowded panel that runs hot — say 55–60 °C near the top — you lose about 5–8 A of headroom. Plan your load accordingly; don't just spec the 63 A nameplate and forget the ambient.
Physical fit and mounting
Dimensions: width 105 mm, height 181 mm, depth 86 mm. That's a 105 mm wide footprint — three-pole MCCB standard, but measure your existing bus or mounting plate before you assume it drops into a panel cut for a different brand.