BJ Enterprises Sentry Tank Monitor, with a control panel that can be mounted almost anywhere for easier accessibility, is a 2-piece, battery-operated unit designed to indicate a low or high tank level by sounding a 103-decibel siren. Engineered for use on most single- and double-walled above-ground tanks, the Sentry is primarily used by automotive and industrial markets to help prevent costly and unnecessary tank overflows or untimely inventory shortages, ideal for monitoring interstitial space as well. When activated to an alarm condition, this unit will sound its built-in siren for up to 4 days on a fresh 9-volt battery. A low-cost unit that is easily maintained on-site and simple to install in a 2 tank bung, the Sentry is ideal for remote areas where AC power is not accessible. This unit also features weather-resitant housings for all its buttons, a UL buna sensor, and a 1/2" x 6' pipe that is easily field adjustable to provide a tank depth from 2" to 10'. The Sentry can not be used to run accessories.