These are suitable for conductive liquids like water and for non-conductive liquids like DieselOil. Models for either one level monitoring or two level monitoring. FEATURES Can be used for potable water, water with impurities and for dieseloil Cable size & length no restriction for water level monitoring Suitable for variety of electrodes Optical sensing for dieseloil level monitoring Open collector output (for FRKP4) Choice of enclosures (DIN-Rail, & Plug-in) Use of SMD Technology (S2 Series models)