The 3RV1021-1AA10-ZW96: The 1.6 A continuous rating and 0.55 kW motor power at 400 V AC size this breaker for small motors—pumps, fans, conveyors up to that load. No ground-fault detection on this variant; if that's needed, you'd step to a different suffix or add an external module.
The 45 mm width means it takes one standard 45 mm-wide slot in a panel—no extra side clearance needed (0 mm at the side,). Wire range: solid or stranded 1–2.5 mm² (two conductors) and 2.5–6 mm² (two conductors) per terminal. That covers most motor-circuit wiring up to 6 mm². IP20 front protection means it's safe for finger contact in a closed panel but not for washdown environments.