SD card slots are a common feature on laptops and other portable devices, as they allow users to easily store photos, music, and other files. Some laptops even come with SD card readers that allow users to easily transfer files to and from their SD cards.
SD card slots are not always universally available, however. Some ultra-portable laptops, such as the MacBook Air, do not have SD card slots.
This may be due to space constraints or because the SD card reader is not included in the purchase price. Laptops that do have SD card slots may also only have one slot available.