APC Smart-UPS Online 48V External Battery Pack, 2U Rackmount, Lithium-Ion Intelligent Battery Management System 2U Lithium-Ion Battery Pack Overvoltage and overtemperature protection Rack Tower Convertible Form Factor Scalable Runtime Extended-runtime lithium-ion battery pack provides much higher energy density and scalable runtime to Smart-UPS applications. The APC Smart-UPS On-Line Lithium-ion Extended Runtime Battery Pack offers flexible rack and tower installation options and provides 3X the battery life when compared with a VRLA battery. Compatible with SRTL 1-3kVA systems, this versatile 2U long runtime battery is perfect for critical long runtime applications in network IT and other applications. Main Input Voltage 48 V DC Number of rack unit 2U Battery Type Li-Ion (Lithium Ion) Provided Equipment 4 post rail kit Communication Cable Grounding Cable Installation guide Rack Mounting brackets Battery Capacity 50 Ah