Extended-run battery systems provide flexible runtime to critical Smart-UPS applications External Battery Pack for use with APC SMX model UPS (1500 VA or lower). This external battery pack does not funcation on its own, but must be used with an SMX model UPS. Compatible with the following APC SMX models of UPS: SMX750, SMX750NC, SMX1000, SMX1500RM2U and SMX1500RM2UNC Multiple battery pack configuration: connect up to 10 battery packs for extended runtime applications Includes: Installation guide, Rack Mounting brackets