The model WB-200 operates on 12 or 24 Volt AC/DC and has a form C relay output that can be connected to alarm panels, bells, dialers, etc. The unit can monitor up to as many as six sensor probes, up to 100 feet away. Each sensor probe has two contacts. When a film of water forms a bridge between these contacts, the unit senses this and triggers the alarm output. The sensor will not alarm due to condensation or high humidity. One standard surface sensor is included with the unit.