It's a thermal-magnetic MCB for AC distribution circuits, with a breaking capacity of 3 kA Icu at 400 V AC 50/60 Hz, certified to SANS 60947-2. The C-curve means magnetic tripping occurs at 8.5 x In (170 A) within a +/-20% tolerance — standard for general-purpose loads like lighting, socket outlets, and small motor circuits where inrush isn't extreme. For a distribution board fed by a transformer with modest fault levels, this is adequate; if your calculated prospective short-circuit current exceeds 3 kA, you'll need a higher-rated device or a current-limiting upstream breaker.
Clip-on mounting to DIN rail, 72 mm wide (4-pole width at 18 mm per pole), 81 mm tall, 66.5 mm deep. That's a standard footprint for a 4P MCB — no surprises on the DIN rail, but check the gland plate depth if you're squeezing it into a shallow enclosure. Pollution degree 2, so it's rated for normal industrial environments with only non-conductive contamination.