HP A3232-69107 - 20 slot midplane board - 20 Slot Midplane Board - Vertical Interconnect Board (in the Center of the Disk Array) Retail
HP A3661-69004 - 30 slot midplane board - Vertical interconnect board (in the center of the Disk Array) Retail
HP A6961-67105 - Midplane riser board - Has slots for the processor board, memory board, and I/O base board Retail