Its interrupting capacity hits 187 kA at 240 V AC, dropping to 121 kA at 415/440 V, 75.6 kA at 500 V, and 3 kA at 690 V — the 690 V figure tells you this is a 240–500 V workhorse, not a 690 V main breaker. The 756 A value is the rated ultimate short-circuit breaking capacity (Icu) under test conditions, not a continuous rating. The continuous current is 63 A.
That 105 mm width is the standard 4-pole-module width for a 3-pole MCCB in the SENTRON 3VA frame — it occupies three 27 mm pole pitches plus a bit of frame.
What the auxiliary switch configuration tells you
This unit ships with 3 auxiliary switches (HQ type) built into the basic switch assembly. The base order code 3VA20635HN320AA0 is the supplied switch platform.