A set of roller conveyors is described, the members of which include a plurality of driven rollers disposed in two parallel tracks. Each member of the set has at least one electric feed-in block, which is connectable to the locally available system voltage and from this generates an output voltage, which is the same for all members of the set and is lower than or equal to the lowest system voltage, for which a member of the set is designed. The drive motors of the driven rollers are in this case designed for the output voltage of the feed-in block. In this way, the manufacturer of the roller conveyors may carry out the design, warehousing, and assembly of a roller conveyor independently of the different system voltages available from site to site and in this way may considerably reduce the costs associated therewith.