The Intel® RAID Smart Battery AXXRSBBU3 (BBU) is an optional accessory for selected RAID controllers and to support the ROMB (RAID-on-Motherboard) solutions used on Intel® Server Boards and Platforms. The BBU preserves the contents of the RAID DIMM if the power drops below specifications. It ensures that following a power failure or other fatal event, all data on the RAID cache DIMM is flushed to the hard disk drives.