Star Tech. com 4 Port Native PCI Express RS232 Serial Adapter Card with 16550 UART Add 4 RS-232 serial ports to your standard or small form factor computer through a PCI Express expansion slot Native single-chip, single lane PCI Express chipset delivers true PCIe performance, up to 48% more efficient than bridge chip designs Standard and low profile/half-height brackets included to ensure fitment in any system The PEX4S553 4-Port Native PCI Express RS232 Serial Adapter Card with 16550 UART lets you add 4 RS232 (DB9) serial ports, using a single PCI Express expansion slot. Based on a native single-chip design, this 4-port serial adapter card allows you to harness the full capability offered by PCI Express (PCIe), while reducing the load applied to the CPU by as much as 48% over conventional bridge-chip serial cards. The RS232 Serial Adapter Card includes 4 half-height/low-profile brackets, allowing the card to be installed into almost any PC case, regardless of form factor. Backed by a Star Tech. com Lifetime warranty and free lifetime technical support. What?s in the box 4 Port PCI-Express RS-232 Serial Card Bracket with 2 DB9 male ports Low Profile Brackets Driver CD Instruction Manual