LinkMejor Stainless Steel Wired Side Mount Liquid Level Sensor Floating Switch

A Float switch is a device used to sense the level of liquid within a tank. The switch may actuate a pump, an indicator, an alarm, or other device. Note: because the current that the switch can carry is much little(0.5a), you must use a relay or Contactor when it is connected by a load, relay or Contactor are not included here