MicroSD (micro SD) cards were originally called T-Flash and then TransFlash before being renamed as microSD when adopted by the SD Card Association (SDA). Like its name, the microSD card/ TransFlash is essentially an SD card, but in a much smaller package (the size of a fingernail). It is one of the smallest removable flash memory card formats designed specifically for mobile phones and other small devices. Like any flash memory card, it can be used to store various types of files, including photos, videos, music, or software.