The white wires are fied either in a container or anywhere water accumulates at the level you wish the alarm to sound. When the water level reaches the bare parts of the wire the alarm sounds.
The white wires are 1 Metre long and can be etended or substituted with any type of wire and a length of 100 Metres!! has been used in testing.

85dB @12V dc at 30cm

This alarm consumes virtually no power (less than 1uA) when not triggered and 30mA when it is.

12 Volt DC supply is needed, NOT SUPPLIED