Mini Stainless Steel Tank Pool Liquid Water Level Sensor Horizontal Float Switch This is a stainless steel float swith,contains no mercury. This float switch is a device used to sense the level of liquid within a tank,the switch may activate a pump,an indicator,an alarm,or other device. It does not have a complex circuit,will not be disturbed,as long as the material selection,liquid,pressure or temperture can be used in any environment. The versatility of this vertically monted sensor means that it can be installed either at the top or base of your tank,depending on whether you wish to detect the water's rise or fall. The float level switch is widely used in electronic,electrical,chemical,water treatment,drainage and other walks of life level control and alarm. Material:Stainless steel. Alternating current: 220v.