Full Details from Amazon.com : http://www.amazon.com/gp/product/B001H3KG6W?tag=onigi-20
StarTech.com 2 Port Native PCI Express RS232 Serial Adapter Card with 16950 UART (PEX2S952)
Data transfer rates of up to 460 Kbps for peak serial device performance
Native single-chip single lane PCI Express offers increased speed and reduced CPU load by up to 48
Standard and low profile bracket included ensuring easy installation into almost any system
Two high speed RS-232 serial ports with data transfer rate up to 4608 Kbps
Compliant with PCI Express base specifications revision 10a
Includes half-heightlow profile mounting bracket