SIRIUS contactors with a width of 45 mm (size S00/S0), 55 mm (size S2), and 70 mm (size S3) come with a uniform, versatile range of auxiliary switches and accessories, which are quick to retrofit and replace. The accessories for contactor relays and power contactors are identical in design. The accessories can be attached on the front or the sides of devices. The 3RH2 contactor relays can be expanded to give versions with a maximum of 8 poles by attaching 2-pole or 4-pole auxiliary switch blocks.