Secure Digital

'Secure Digital (SD) is a type of non-volatile memory used in memory cards, often used in digital cameras and other compact devices needing means of storage and data transfer.

Sizes

 * SD
 * MiniSD
 * MicroSD

Formats

 * SDHC
 * SDXC
 * SDIO

Links

 * Wikipedia article
 * Official website
 * SD Simplified Specifications