It provides LI protection — thermal overload (L) and magnetic short-circuit (I) — in a fixed-mount, 3-pole (3D) package rated 160 A at 50 °C.
Rated 160 A at 50 °C ambient — that is the continuous current the trip unit can carry without nuisance tripping in a typical panel environment. At higher ambient temperatures you would need to derate or step up to the next frame size. Instantaneous magnetic pick-up is fixed at 1250 A — roughly 7.8 x In. That means it clears hard short-circuits fast, but does not offer adjustable magnetic thresholds; if your coordination study needs a different Ii setting, you would need a different trip unit (e.g. Micrologic). Thermal overload (Ir) is adjustable from 0.7 to 1.0 x In (112–160 A), with a fixed long-time delay of 120–400 s at 1.5 x In and 15 s at 6 x Ir. That covers most feeder and light motor-start applications without needing a separate relay.
This is a trip unit — it snaps into the ComPacT NSX250 breaker frame, not onto a DIN rail by itself. The breaker mounts fixed (not plug-in or drawout) in a panel or enclosure.
Class II electrical shock protection — no earth connection required on the trip unit itself.