The CyberPower BP36V60ART2U (36V) External Battery Module (EBM) with DC plug-n-play connections and Fast Charge Technology provide extended battery run-time during power outages for select Smart App Online UPS models. Up to 10 EBMs can be added and fast charging times are maintained thanks to each EBM having a built in battery charger. The typical charging times of 5 hours for the OL1000RTXL2U and OL1500RTXL2U are maintained whether there are 1 or 10 EBMs installed.Each EBM takes up 2U of rack space and can also be installed in a tower form factor to match the UPS. A DC plug-n-play power connector make it easy to daisy-chain additional EBMs to a UPS system. CyberPower Smart App Online BP36V60ART2U 1000 and 1500VA UPS External Battery Module is one of many UPS/Battery Backup Accessories available through Office Depot. Made by CYBERPOWERPC.