Low-frequency external vibrators are mainly used for power feeders, screens, grizzlies and shake outs as well as in industries, especially on vibrating tables, for compacting bulk materials, or in the casting industry for moulding and coring compaction. They are specially designed for heavy duty jobs, as well as for handling heavy and wet material. As they are self-synchronizing, the ER low-frequency vibrators may be used in groups of two, located opposite one another in order to generate a linear vibration.