This is the part you'd land on when the BOM calls out an XT1N 125 TMF and the line needs a breaker that fits the standard DIN-rail or panel-mount footprint of the XT1 family.
What the XT1N 125 TMF means for fit
The 125 A frame and TMF (thermal-magnetic fixed) trip unit cover motor and distribution protection in a compact package. The XT1N series is ABB's standard-duty MCCB line — sized for panel builders who need a UL 489 / IEC 60947-2 listed breaker that doesn't eat up DIN rail space. The TMF trip gives a fixed thermal and magnetic setting, so no field adjustment; you spec it for the load and it stays there.