Siemens SENTRON 3VA2125-0KP32-0AA0 — 25 A MCCB with ETU850 Trip Unit
It's designed for line protection in distribution panels, with a 440 kA breaking capacity at 415 V AC — that's the figure that governs its fault-clearing capability in a 400 V class system, not the lower 187 kA at 690 V. The ETU850 gives you adjustable N-conductor protection from OFF to 40%–160%, and the breaker carries a communication function for integration into monitored networks. On the front, it's IP40 — fine for enclosed panels, not for washdown zones.
That's unusual; most breakers start dropping current above 40 °C. The 300 A maximum and 38 A minimum are the adjustment limits of the ETU850, not the breaker's thermal capacity.
That width is three pole spaces on a standard DIN-rail grid — measure your enclosure backplate before ordering. The depth of 86 mm means it clears most 200 mm deep enclosures, but check gland-plate clearance on shallow boxes.