At 690 V the breaking capacity drops to 10 kA — still enough for most 690 V motor circuits. No ground fault detection on this variant, so pair it with a separate ground-fault relay if needed.
The 45 mm width means it takes up two standard 22.5 mm module spaces — slim enough for a crowded panel. That's the space needed to keep heat from building up and to allow the bimetal strip to track ambient correctly. If you cram it tighter, you'll nuisance-trip on a warm day.
What the ratings mean in practice
That's typical for a motor branch circuit fed by a large transformer. At 240 V the same 100 kA holds; at 690 V it's 10 kA. No derating curve is given in the spec, but standard practice is to reduce the thermal setting by about 0.5% per °C above 40 °C ambient. Keep that in mind if your panel sits next to a furnace.