"This Harmony RSLZ plug-in relay socket has a coil control voltage of 12 - 24V AC/DC." "It has large choice of number of contacts for high rated current use." "It also offers LED indicator and protection circuit." "It helps to reduce the size of enclosures and increase machine reliability, you can mount nearly everywhere." "One of the slimiest socket on the market, with 6.2mm width, it can be installed nearly anywhere." "Workability for hard-wired logic automated systems to complement the functions of industrial programmable logic controllers (PLCs)." "Status display with LED, clearly signal both in the day and night."