The 40 A rating holds up to 55 °C ambient before the first derate step — at 65 °C it's still good for 38 A, so you don't lose a lot of headroom in a warm enclosure.
This MCCB delivers 121 kA interrupting capacity at 240 V, dropping to 75.6 kA at 415 V and 52.5 kA at 440 V. Those numbers mean it can sit upstream of a high-fault panel without cascading — useful when you're coordinating with downstream branch breakers and need the main to hold.
The case measures 130 mm tall, 101.6 mm wide, and 70 mm deep — a standard footprint for a 4-pole MCCB in this class. It mounts to a backplate or DIN rail in a distribution board.