A PCI-Express network card is a type of computer hardware that allows a computer to connect to a network. PCI-Express cards typically have one, two, or four ports and can connect to networks with speeds of 10, 100, or 1000 Mbps. Some PCI-Express cards have multiple ports so that they can connect to multiple networks. For example, a dual port card could be used to connect a computer to a LAN and a WAN. Quad port cards are typically used to connect multiple computers to a single network. These cards can also have different speed connections. For example, a card with four 10 Mbps ports could be used to connect four computers to a 10 Mbps network. Or, a card with two 100 Mbps ports and two 1000 Mbps ports could be used to connect two computers to a 100 Mbps network and two computers to a 1000 Mbps network.