The Legrand DX3 RCBO AC Type FP 40A 300mA is a four-pole safety device specifically engineered for residential final circuits. It integrates earth leakage, overload, and short circuit protection into a single 72mm unit, eliminating the need for a separate backup MCB. Rated for 415V at 50Hz, it serves as a robust shield for whole-house electrical networks against multiple fault types.