This Harmony RPM power plug-in relay has a coil control voltage of 24V AC and has 4 changeover contacts 4PDT (quadruple pole double throw) with a rating of 15A.It has large choice of number of contacts for high rated current use.It helps to reduce the size of enclosures and increases machine reliability, you can mount nearly everywhere.Plug in type enables easy installation and maintenance.Workability for hard-wired logic automated systems to complement the functions of industrial programmable logic controllers (PLCs).