There are three different types of internal PCI slots for laptop and notebook computers. The traditional Mini PCI slot (shown first), the full height Mini PCIe slot (shown second), and the half height Mini PCIe slot(shown last). The Mini PCI cards are 59.6 × 50.95 mm, the full height Mini PCIe cards are 30×50.95 mm, and half height Mini PCIe cards are 30×26.8 mm.
Most systems have an M.2 Key E or Key A slot for wifi cards (see M.2 wifi card page for details)
Most newer systems have at least one half height Mini PCIe slot during this time frame.
2005 and 2010
Most systems during this time frame have at least one full height Mini PCIe slot.
1999 and 2005
Most systems during this time frame came with a Mini PCI slot.
If your system did not come with a wifi card a universal wireless antenna may be required.
Examples of what Mini PCIe and Half Height Mini PCIe cards look like when installed
Full and Half Height Mini PCIe cards are generally used in laptops. However some desktops do support them. If you have a desktop computer with such a slot it'll look something like the below picture. Notice that there is an external antenna. This does not come with the card. If you need such an antenna we will be happy to discuss what your options are any any antennas that we may stock.
This is the bottom of a laptop and shows an installed Full Height Mini PCIe card. Next to it is a Half Height Mini PCIe card for comparison: