This is the disconnect and protection device for a branch circuit or motor load center, sized for panel building where a compact, high-breaking-capacity switch is needed without the adjustability of an electronic trip.
The lifecycle stage for this order code is listed as current.
The description string "XT1S 125 TMF" decodes the key fit parameters: XT1S is the frame size (125 A max, compact footprint for DIN-rail or panel-mount), and TMF indicates a thermal-magnetic fixed trip unit — no interchangeable rating plugs, no electronic adjustment. The trip curve is factory-set, so the order code alone determines the overload and short-circuit protection thresholds. Verify the TMF rating matches the downstream conductor and load before committing the BOM line.