The same 100 kA rating holds at 240 V, 500 V, and 690 V AC, so the part covers a wide range of supply voltages common in industrial plants.
The 45 mm width is a standard 2.5 module footprint on a DIN rail — useful when estimating fill factor on a panel's gland plate. Clearance requirements: 50 mm upward and downward, 30 mm to the side, and zero forward or backward clearance needed. That zero forward clearance is a practical advantage in tight enclosures where you're stacking breakers close to the door.