It carries a rated operational current of 125 A at 400 V AC-23A/AC-23B, and a breaking capacity of 1000 A at 400 V AC-23B. That AC-23B duty class means it's rated for switching motor loads and other highly inductive circuits — not just resistive heating — so it's a fit for motor branch circuits in panel builds.
The 125 A conventional free-air thermal current (Ith) at 40 °C is the baseline for continuous current in open air; the AC-23A/AC-23B ratings at 400 V, 500 V, and 690 V define how much motor load it can switch at each voltage. The making capacity of 1250 A at 400 V AC-23B covers the inrush when closing onto a fault. It complies with IEC 60947-3 (switch-disconnector standard) and IEC 60269-2/1 (fuse standards), which is the baseline for industrial control panels in most markets. The 8 kV rated impulse withstand voltage (Uimp) gives it a solid margin for surge environments in industrial power distribution. Mounting is on a rail or plate, and the external left-side handle operation suits panel layouts where the handle needs to protrude through a door cutout.