The 100 A fixed rating (Ir=100 A non-adjustable) means overload protection is set at the factory — no field dial to turn, so the BOM line is locked once specified. The short-circuit release is fixed at 10 x In (1000 A), which suits distribution and feeder applications where you want a moderate magnetic pickup to ride out motor inrush without nuisance tripping. Class B means it's rated for full selectivity with an upstream device — useful in a panel where you need the downstream breaker to clear first and keep the rest of the bus live. The lug terminal is sized for DC power applications — the OEM variant is built in China and carries the -ZD00 suffix for that supply chain.
Four poles at 100 A mean the breaker occupies the full frame width — plan for a minimum 25 mm of DIN rail per pole plus the operating mechanism overhang. The lug terminals accept conductors sized for a 100 A feeder; verify your lug crimp tool matches the terminal tunnel dimensions before terminating.