The A9F07370: The 0.5 A In is the continuous current the breaker carries without tripping — sized for a low-current load like a signal transformer or a small power supply, not a motor or heater bank. The C-curve (magnetic trip at 8 x In +/- 20 %, so 4 A nominal) means it holds through moderate inrush, typical of small transformers and capacitive loads, but trips fast on a hard short. The 70 kA Icu at 415 V is the maximum fault current it can interrupt once without damage — that's a high-fault rating for a 0.5 A MCB, so it can sit on a panel fed by a large transformer without needing a current-limiting fuse upstream. The thermal-magnetic trip unit covers both overload (thermal bimetal) and short-circuit (solenoid).
Snaps onto a DIN rail (mounting support: DIN rail). The 3-pole body takes 6 x 9 mm pitches on the rail — 54 mm wide, 91 mm tall, 78.5 mm deep. Terminals accept double conductors up to 25 mm² rigid or 16 mm² flexible; wire strip length is 14 mm. IP20 rated, so it's for inside the enclosure only. The toggle control and trip indicator give local status without opening the door.