Self contained tank monitor designed for use on single or double wall aboveground tanks. Float sensor can easily be adjusted for sensor depth from 2” to 10’ and may be used to monitor interstitial space of double walled tanks. When activated to an alarm condition, the alarm sounds a 103 decibel siren for up to 4 days with a fresh 9 volt battery. An optional transformer, P/N 100556 may be connected to eliminate battery operation. Intended for indoor use.