The key spec here is the interrupting capacity: 121 kA at 240 V AC, dropping to 75.6 kA at 415 V and 52.5 kA at 440 V — that's serious fault-clearing capability for high-available-fault-current installations like main switchboards or large sub-distribution boards.
Breaking capacity — what those numbers mean for your panel
The 121 kA at 240 V and 75.6 kA at 415 V tell you this breaker can safely interrupt a fault current up to those levels without welding its contacts or exploding the arc chamber. The 11.9 kA rating at 690 V is what you'd use for 600 V class systems in Canada or some mining applications.
The breaker measures 76.2 mm wide (3 inches), 130 mm tall, and 70 mm deep. The depth of 70 mm means it fits flush in most enclosures without protruding past the deadfront. The trip indicator gives a visual flag when the breaker has tripped on fault, which helps a field tech identify the problem circuit without pulling the cover.