CyberPower's ABP72VRM-2U 72V Extended Battery Pack offers extended runtimes for the OL2000RMXL2U & OL3000RMXL2U UPS. These 2U packs not only esthetically match the UPS's, but can be rack or tower mounted, just as the UPS's. The heavy gauge power cord is adapted with plug-n-play DC connectors for easy installation. The all-metal enclosure safely houses the 12 (twelve) 12V 9Ah batteries, which are connected via 2 strings of 6 in serial. Up to 4 battery packs can be daisy-chained to the UPS for extended runtimes up to 275 minutes.