PSSu BS-R 1/8 S 312652 Carrier units for the I/O modules and supply voltage modules. These modules are simply inserted on to the base modules and are easy to change when making system adjustments. PSSu, base module for supply voltage modules, infeed module supply, infeed periphery supply, infeed C-rail, 1-row, 4 connection levels, 8 terminals, screw connection. Only to refresh the supply voltage and to form supply groups.