Have bought 3 of these now and can not praise them enough
It has saved my v8 speed boat twice now
One time when it sucked up sea weed and stopped water flowing around engine it sounded and alerted me to an issue
Second time In same v8 boat the impeller failed stopping all water flow and the alarm sounded again saving my v8 for second time
So all in all the the small out lay has saved me $10,000 plus in engine rebuilds
If your thinking about getting one stop thinking and do your self a favour and just buy it before you wish you had