The Schneider Electric DOM11377 is a Domae-series miniature circuit breaker — 1 pole, 16 A rated current, C-curve trip characteristic, with a 6 kA breaking capacity at 230/400 V AC per IEC 60898-1.
This order code is marked obsolete by the manufacturer. No direct successor order code is published under the Domae range.
The 1P (single-pole) form protects one phase; for a 230 V line-to-neutral circuit, that is the standard fit. The 18 mm width per pole is the standard DIN-rail module pitch — one module wide, so it occupies one 18 mm slot on the rail.
The 78.5 mm depth and 81 mm height fit within the envelope of a typical distribution board.