This fully encapsulated mechanical Float Switch is goof-proof, making life easier by providing automatic control of the fluid level in the tank. Regulate the water level by lengthening or shortening the power cable and securing it with a band clamp or zip tie. The Float Switch is rated at 15 amps at 12 volts, or 13 amps at 120 volts. It can be connected to either fill a tank (off when full) or to drain it (on when full) - this is what is meant by SPDT (Single Pole, Double Throw). It is not sensitive to rotation or turbulence, allowing it to be used in both calm and turbulent applications. Safe for domestic water.