The Schneider Electric DOMF01240 is a Domae-series miniature circuit breaker (MCB) with a C-curve trip characteristic, rated 40 A at 230 V AC, 2 poles, and a breaking capacity of Icn 6000 A per IEC 60898-1. Rated 40 A continuous, so it protects a 40 A branch circuit against sustained overloads.
Width is 36 mm (2 modular pitches of 18 mm), which is standard for a 2-pole MCB. Depth 71.5 mm, height 81 mm — fits any standard distribution board or sub-panel. Terminals accept rigid cable up to 35 mm² or flexible up to 25 mm²; strip length 14 mm, tighten to 3.5 N·m. The neutral position is on the left, so busbar comb alignment matters if you're feeding a multi-pole group. IP20 finger-safe on the front face; IP40 inside a modular enclosure.