The ABB 2CSR255180R1204 is an RCBO breaker with an rated current (Inom) of 20A, tripping current (Ires) of 30mA, 1+N poles, rated voltage of 230VAC, a DIN rail mounting style, and IP20 degree of protection. It is designed to be used in a range of residential and commercial applications, providing reliable protection against overloads, short circuits, and earth leakage.