Overload protection is fixed at Ir=125 A; short-circuit protection trips at Ii=10 x In (1250 A).
The fixed Ir=125 A overload setting suits a dedicated 125 A feeder — no adjustment range, so the load must match that rating exactly. The Ii=10 x In fixed short-circuit setting provides a 1250 A magnetic trip threshold; this is typical for line protection of cable runs or non-motor loads where no high-inrush startup current is expected. The undervoltage release (UVR) at 24 V DC allows a safety circuit or emergency-stop chain to drop the breaker on loss of control voltage, common in machine-tool and conveyor guarding applications. On a panel swap or retrofit, having that hardware on the breaker saves a trip back to the van when the original nuts are rusted or missing.