The interrupting ratings tell you where this breaker can be applied: 187 kA at 240 V, 121 kA at 415 V and 440 V, 79 kA at 500 V, and 5.1 kA at 690 V.
Above that it derates: 241 A at 55 °C, 232 A at 60 °C, 222 A at 65 °C, and 213 A at 70 °C. If the panel ambient runs 60 °C, size the load at 232 A continuous — not the nameplate 250 A.
Both are serviceable spares if the main breaker body is in the panel and only the trip unit or aux switch needs replacement.
What it does not include
The shunt trip (STL) is the only auxiliary release fitted; if you need undervoltage protection or remote comms, this variant is not the one.