The ETU320 trip unit gives you adjustable thermal and magnetic settings, so you can coordinate selectivity downstream without swapping hardware. Breaking capacity is the headline: 242 kA at 240 V, 187 kA at 415 V and 440 V, still 121 kA at 500 V. For most 400 V industrial services, 187 kA SCCR means it can sit upstream of a transformer or a large motor starter without worrying about cascading failure.
That's a 4-pole frame in a standard SENTRON 3VA footprint — it bolts into the same mounting pattern as other 3VA breakers in this current class.
What the ETU320 trip unit gives you
It's not a communicating unit — no Modbus, no PROFIBUS, no remote signaling — but it does have a trip indicator (mechanical flag) so you can see which breaker opened without opening the panel door.