The Siemens 3VA1112-6GD42-0AA0-ZD00 is a 4-pole IEC frame 160 molded case circuit breaker with a 125 A continuous rating and a 70 kA interrupting capacity at 415 V (breaking capacity class H). It carries the TM210 line protection release — thermal-magnetic, fixed at 125 A overload (Ir) and 10 x In short-circuit pickup (Ii). The FTFM (Fixed Thermal Fixed Magnetic) designation means both the thermal and magnetic trip elements are factory-set, not field-adjustable, so what you see on the nameplate is what protects the circuit.
The 125 A fixed Ir means it is sized for a 125 A continuous load, not a range; if your BOM calls for 125 A protection, this is a direct fit. The 4-pole configuration with 100% N conductor protection means the neutral pole is fully rated and switched, required on 4-wire systems where the neutral carries unbalanced load current and must be protected like a phase conductor. The nut keeper kit and DC Power OEM in China designation in the description indicate this variant was produced for a specific OEM build — the nut keeper secures the breaker in a DC power cabinet application.