To help prevent overflows while pouring a cup of coffee, try a liquid level indicator. Device hangs over the edge of a cup and makes noise as the liquid approaches the top of the cup. With this 9 volt, 2 stage liquid level indicator, a slow beep will sound as liquid nears the top, and then a faster, higher pitched beep will sound once it has reached the top. No more messy overflows! Uses 1 9V battery, which is inluded.