The dual trip mechanism means one device handles both the sustained overload curve (thermal) and the instantaneous fault clearance (magnetic), saving a slot versus separate overload relay and contactor combinations.
What the dual trip means for your BOM
The delayed thermal element provides time-band selectivity downstream, so nuisance trips on motor inrush don't happen; the magnetic element clears a hard short in under a cycle. That combination is standard for feeder protection in industrial panels — one MCCB per motor or distribution branch, coordinated with upstream main breakers.