Breaking capacity is the headline number here: 121 kA at 240 V AC, dropping to 75.6 kA at 415 V and 52.5 kA at 440 V. It's a line-protection version (Product version: Line protection) with no communication function and no ground-fault monitoring built in. If you need those, you're looking at a different variant in the 3VA family. The IP40 rating on the front means it's splash-resistant from the panel face but not washdown-rated — standard for indoor switchgear.
Duty and derating in the enclosure
Thermal derating is modest: the breaker carries 25 A at 45 °C and 50 °C, drops to 24 A at 55 °C and 60 °C, then to 23 A at 65 °C and 70 °C. That's a 2 A loss over a 25 °C rise — about 8% — so if your panel ambient runs hot near the upper operating limit of 70 °C, you still get 92% of rated current. Physical footprint: 101.6 mm wide (4 in), 130 mm tall (5.12 in), 70 mm deep (2.76 in). That's a standard 4-pole MCCB width — it'll fit a SENTRON panelboard or a DIN-rail adapter without surprises. Power loss is 8.5 W maximum, which is low enough that you don't need forced ventilation in a typical enclosure, but group it with other high-loss devices and check the thermal budget.