Argus BB-DCM12-90 Battery Bug Deep Cycle Battery Monitor for 20-90Ah 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, 20 - 90 amp-hour deep cycle batteries