The SENTRON 5SQ2570-0KA01 is a 2-pole miniature circuit breaker wired as 1P+N — it switches the line and switches the neutral, so you get full isolation on a single-phase 240 V AC circuit. The 3 kA breaking capacity (per EN 60898 and IEC 60947-2) is sized for residential and light commercial sub-distribution where the prospective fault current stays under that threshold.
The breaker occupies 2 width units on a DIN rail and installs at 55 mm depth, which fits standard 63 A and 100 A distribution boards. Overvoltage category 3 and energy limiting class 3 mean it coordinates with downstream loads and upstream protective devices in a typical TN or TT system.