4 x drive bay Tower RAID system. 1" high SATA II drive bays, Extended PCI-e host interface. 256MB SDRAM cache (upgradeable up to 1GB). Supports multiple RAID sets. Hot swap PSUs (2) and hot swap fans. Support for RAID level JBOD, 0, (0+1), 5, 6 and global spare. Includes PCI-e cable, PCI-e HBA and 2 x Power cords.