The Schneider C120N is a 4-pole circuit breaker rated 125 A continuous, with a breaking capacity of 10 kA at 400-415 V AC. The 6 kV rated impulse voltage (Uimp) tells you it handles surge events common in industrial mains without flashover. Rated insulation voltage (Ui) is 500 V AC, so the internal creepage distances are sized for 480 V systems (common in North American plants) even though the operational voltage is listed at 400-415 V AC. The 50-60 Hz frequency rating covers both 50 Hz European and 60 Hz North American grids without derating.
Dimensions are 81 x 108 x 73 mm — standard Multi9 modular width for a 4-pole unit. Mounts on DIN rail (EN 60715) in any distribution board or sub-panel. The 125 A rating is the highest continuous current in the C120N range, so it's typically used as a main incoming breaker or a feeder to a large sub-panel, not for branch circuits.