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. FEATURESCan be used for potable water, water with impurities and for dieseloilCable size & length no restriction for water level monitoringSuitable for variety of electrodesOptical sensing for dieseloil level monitoringOpen collector output (for FRKP4)Choice of enclosures (DIN-Rail, & Plug-in)Use of SMD Technology (S2 Series models)