Bp36v42 3u racktower external battery pack offers extended battery runtime when used in conjunction with expandable 36v tripp lite rackmount and tower ups systems includes heavy gauge cabling with high current dc connector for safe simple installation included daisychain connector enables the connection of additional compatible 36v external battery packs to the host ups included mounting accessories support 3u rackmount installation in 4 post racks options for 2 post center mounting and up