It carries the ETU560 electronic trip unit, which provides adjustable overload and short-circuit protection curves — the 0.5 to 25 s response time range (tr min. 0.5 s, tr max. 25 s) lets you coordinate selectivity downstream without nuisance tripping. Breaking capacity runs from 440 kA at 240 V down to 53 kA at 690 V, so this breaker handles high-fault utility feeds at lower voltages while still clearing faults on 690 V industrial buswork.
That depth — 86 mm — is the dimension you check against gland-plate clearance and door-swing arc.