It's rated 4 A at 50 °C (conforming to EN/IEC 60947-2) with a K-curve magnetic trip of 12 x In ±20 % DC. That curve means it's designed for DC loads with moderate inrush — think DC power supplies, control circuits, or DC distribution panels where you need a thermal-magnetic trip but don't want nuisance trips from a short capacitive charge. The breaking capacity steps are 20 kA at 110 V DC, 10 kA at 220 V DC, and 6 kA at 250 V DC — so at 110 V it handles a serious fault without upstream coordination worries. It's a category A breaker (no intentional short-time delay), suitable for isolation, and carries an IP20 finger-safe front with IP40 inside an enclosure.
Clip-on DIN rail mount, 18 mm wide (2 x 9 mm pitches), 81 mm tall, 73 mm deep. It's a single-module footprint — standard for a 1P MCB. Tunnel-type terminals top and bottom accept up to 25 mm² rigid stranded, or 16 mm² flexible, with a 14 mm strip length and 2.5 N·m torque. You can land up to three 1 mm² flexible conductors per terminal if you're daisy-chaining. Pollution degree 3 means it's rated for industrial environments with conductive pollution, and tropicalisation class 2 (per IEC 60068-2) handles humidity up to 95 % at 55 °C. The toggle gives clear ON/OFF indication, and the contact position indicator confirms isolation visually. Padlockable for lockout/tagout.