The 18 mm width (one modular unit) fits standard DIN-rail enclosures; the 76 mm depth leaves room for cable management behind the rail.
The B-curve trips between 3 and 5 times rated current (18–30 A for this 6 A unit), which is the standard choice for resistive and general-purpose loads — lighting, small transformers, socket circuits — where inrush is low. The 3 kA breaking capacity (IEC 60947-2) is adequate for residential and infrastructure sub-distribution; it is not sized for high-fault industrial mains. The single-pole design switches the line only, so it is used in single-phase 230 V circuits or as a branch protector in three-phase panels where each pole is a separate MCB.