The Schneider Electric A9K23416 is a 4-pole miniature circuit-breaker from the Acti9 iK60N series, rated 16 A at 30 °C with a B-curve trip characteristic (magnetic tripping between 3 and 5 times In). The thermal-magnetic trip unit handles overloads and short-circuits in one compact package, and the clip-on DIN-rail mount means it snaps into a standard panel without tools.
The B curve (3–5× In) is standard for resistive and general-purpose loads like lighting and socket outlets where inrush is low; it trips fast enough to protect cable but avoids nuisance trips on small motor starts. Four poles let you switch all three phases plus neutral in a single unit, saving DIN-rail space compared to ganging individual single-pole breakers. The 72 mm width (8 × 9 mm pitches) fits standard distribution board cutouts, and the IP20 finger-safe terminals meet basic enclosure requirements.