Adapter cards for desktop systems that plug inside a PCI or PCI Express slot on your motherboard, which can usually be found by taking off the side of your computers case. Many different hardware enhancements can be added with these, not least broadband modems, wirelss networking (Wi-Fi) and wired/LAN network features.

Unlike PCMCIA cards, PCI / PCI Express cards are NOT designed to fit in portable computers. They are designed for bigger desktop computer systems and allow for improved performance because they connect directly into the computer without needing added cables or connections.