What this breaker is and what the ratings mean for fit
The Siemens 3VA1025-4ED42-0AA0-ZD00 is a 4-pole IEC frame 100 molded-case circuit breaker with a 25 A fixed thermal-magnetic trip (TM210) and a 36 kA breaking capacity at 415 V. The 'S' class rating means it handles standard industrial fault levels up to that current without upstream cascading — suitable for most distribution panels and motor branch circuits in a 400 V system. The fixed Ir at 25 A and fixed Ii at 12.8 x In (320 A instantaneous) mean the overload and short-circuit thresholds are set at the factory; no field-adjustable dials, so the BOM line must match the load's full-load current exactly.
What the N-conductor-unprotected detail means
The description notes N conductor unprotected — the neutral pole on this 4-pole breaker is not internally protected (no overcurrent trip on the neutral). That is typical for IEC distribution where the neutral is bonded to ground at the source and does not require overcurrent protection. If the application demands a fully protected neutral (TN-S systems with a switched neutral), this variant is not the right pick.