Add Two PCI & Two PCI Express Expansion Card Slots to a Desktop or Laptop Computer System. The PEX2PCIE4L PCI/PCI Express Expansion Chassis provides a quick & simple I/O expansion solution to almost any PCI Express (PCIe) enabled system. Adding PCI/PCIe cards to a server or workstation, or providing a platform to swap cards between a mobile & desktop setup is a cost-effective & time-saving solution for for maximizing the I/O capabilities of your system. The external expansion chassis adds two full-length (38cm) PCI slots (32-bit/33 M Hz), as well as two PCIe x 1 (single-lane) slots to a host computer through a single PCI Express connection. Providing total bandwidth up to 250 M Bps from the PCIe x 1 host controller card allows the computer to function as though the expansion chassis cards were connected directly to the motherboard. For mobile applications, the Expansion Chassis can be connected to an Express Card- enabled laptop using the Star Tech.com Express Card connection cable (EC2PCI), eliminating the added expense of purchasing different card adapters for the laptop.