Backplane with one PCIe x8 Gen3 and two PCIe x4 Gen3 expansion slots. The OSS expansion target backplane connects to a motherboard through a PCIe or Thunderbolt cable. It supports up to three I/O cards, one PCIe x8 and two PCIe x4. Slots support Gen1, Gen2, and Gen3 I/O cards. Only OSS target adapters can be used in the OSS target slot. I/O cards designed to the PCI-SIG PCIe specification are supported. This is an ideal product for OEM customers who want to add PCIe Gen3 functionality to their downstream devices or for test purposes.