Argus BB-DCM12-300 Battery Bug Deep Cycle Battery Monitor for 100-300Ah Batteries Large Pulse Resistance (LPR) technology provides exceptionally accurate real-time battery information Extends battery life by alerting users to damaging charge conditions Audible alarms and an easy-to-read LCD screen keep users informed of battery status Perfect for marine, RV, camping, construction and other deep-cycle battery applications Compatible with Absorption Glass Mat batteries and all 12-Volt, 100 - 300 amp-hour deep cycle batteries