Rated 25 A at both 30 °C and 40 °C ambient, so no derating headache in a warm enclosure. Maximum operating voltage is 440 V AC in multi-phase operation, and 250 V AC single-phase. That 440 V ceiling covers most 400/415 V three-phase networks with headroom for nominal variations. The DC rating tops out at 72 V, so this isn't your DC string combiner box breaker — keep it on AC circuits.
At 18 mm width it takes up exactly one modular unit, so four of these side by side eat 72 mm of rail — plan your enclosure layout accordingly. Mounting position is any, so you can run the DIN rail vertically if the cabinet layout demands it.