HP AT101-69002 - 6-slot memory expansion board - Plugs in one of four slots on the system I/O board Retail
HP A6144-69102 - PCI I/O backplane board - Has 12 PCI slots - L3000 PCI I/O backplane board - Has 12 PCI slots - Mounts vertically in the chassis Retail
HP A5191-69102 - PCI I/O backplane board - Has 12 PCI slots - L1000/L2000 PCI I/O backplane board - Has 12 PCI slots - in the chassis Retail