The Siemens 5SU1356-7KK40 is a 40A, 30mA Type A RCBO engineered for high-reliability residential final circuit protection. This 2P (1P+N) device integrates earth leakage, overload, and short-circuit protection into a compact 36mm width housing. Made in Germany, it serves as the primary safety barrier for household electrical systems operating at 230V.