To avoid over-filling a glass or cup because it is hard to see the water line, place this useful gadget on the side of the cup. Pour in the water and when the liquid reaches the tip of the 2 prongs, the unit makes a loud persistant sound, until your remove it from the water. It operates on a 9-volt battery (included) which is easy to install and replace. Without the battery and excluding the prongs, it measures 1.75" x 1" x .93".

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