It's a 4-pole unit with an ETU550 electronic trip unit, designed for line protection and fitted with a communication function for integration into monitored distribution.
The 100 A frame is the continuous current rating — it's the number you match to your load's full-load amps. The ETU550 is an electronic trip unit, meaning you get adjustable long-time, short-time, and instantaneous pickup settings, plus ground-fault protection if the version is so equipped (this one is not — it's the 'without' ground-fault monitoring variant). Breaking capacity is the real differentiator here: 330 kA at 240 V AC, 242 kA at 415 V and 440 V, 187 kA at 500 V, and 3 kA at 690 V. The 690 V figure (3 kA) is lower, so verify coordination if using the breaker on a 690 V system.
The 140 mm width for a 4-pole frame is standard for this class — it's the dimension that determines how many poles fit across a panel or switchboard section. The 86 mm depth is the projection from the mounting surface, important when sizing enclosure depth for door clearance and cable bending radius.