The Siemens 3VA1120-5GD42-0AA0-ZD00 is a 4-pole IEC frame 160 molded-case circuit breaker with a 55 kA interrupting capacity at 415 V — that's the class M breaking capacity, meaning it clears faults up to that level without the arc flashing over, which is the spec that decides whether this breaker holds its downstream gear in a high-fault panel. Overload protection is fixed at 20 A (Ir = 20 A) via the TM210 thermal-magnetic trip unit; short-circuit pickup is set at 16 times the rated current (Ii = 16 x In), so it rides through motor inrush but trips fast on a bolted fault. The neutral conductor is protected at 100% — no derating for the N pole. This variant includes a nut keeper kit and is configured for DC Power OEM applications in China — the nut keeper keeps the terminal hardware from backing off under vibration in a panel that ships as a subassembly.
The nut keeper kit and the China OEM configuration are part of the order code, so the quote matches exactly what lands on the dock.