Secure Digital (SD) Memory Cards - An SD card (Secure Digital memory cards) is a small, easy-to-use memory storage device made for a broad range of uses. The SD card makes sharing data between different computers easy, and is compatible with a wide variety of makes and models of computer. The format is already supported by over a thousand companies around the world. The SD Card is the standard memory card for digital connectivity. With its initial maximum capacity met, SD cards have expanded to the SDHC Card format, offering new levels of storage capacity. SD Cards are so popular that there are even Flash Memory Duplicators just for them and, unlike CDs and DVDs, cannot be scratched.

The SD card is a slightly unusual shape, but this is purposefully built into the design. It is asymmetrical so that it will not be inserted upside down. Another neat design feature is the fact that the card's electrical contacts are buried beneath the surface of the card, effectively protecting them from the fingers of the user.