HP Smart Array BBWC battery pack 398648-001-RFB is a refurbished battery module for battery-backed write cache in RAID controller systems. It is intended for Smart Array P400 and P800 SAS controller boards, as specified in the listing.
The module uses nickel-metal hydride (NiMH) technology and has a rated voltage of 4.8 V. It is listed as one black battery pack, providing a replacement battery module for the supported controller setup.