This is a safe non-mercury mechanical float switch that will automatically turn a pump OFF when a holding tank is FULL (normally closed), then turn the pump ON when the tank begins to EMPTY.  A heavy duty cable clamp (included) is used to attach the 10 foot electrical cable to the tank and the turn-on and turn-off level is adjustable by simply adjusting the point of attachment. The switch can be wired directly into one of the wires between the pump and the power source, or it can also be used with a relay.

$45 POSTPAID TO USA.
$45 TO OTHER COUNTRIES WORLDWIDE ONLY IF ORDERED WITH A PUMP.