675039-001Hard drive blank (cover) - To fill empty large form factor (LFF) drive bays
790497-001Processor blank (cover) - Screws to the top of the second processor socket and helps directs airflow to processor one socket and memory modules
790538-001PCI blanking cover - To fill empty system board PCI slot or when filled with PCI riser board
790539-001Riser cage blank - Covers the two optional horizontal PCIe slots above the power supply cage