It protects a single-phase final circuit against overload, short-circuit, and earth leakage in one 18 mm-wide module. Breaking capacity is 4.5 kA per EN 60898 and 5 kA per IEC 60947-2, sufficient for most domestic and commercial distribution boards where the prospective fault current stays under those thresholds.
The 16 A rating applies at 30 °C ambient. In a warm panel — say 45 °C — the continuous current drops to 14.72 A; at 55 °C it is 13.76 A; at 70 °C it is 12.32 A. If the circuit is loaded near 16 A and the enclosure runs hot, the RCBO will trip on thermal overload at a lower current than the nameplate suggests. That is the derating curve to check against the actual load and panel temperature.
Width is one modular unit (18 mm) — snaps onto standard DIN rail. Depth is 77 mm (installation depth 70 mm).