From the manufacturer:MicroSD is the smallest memory card in the world and the newest standard SD flash memory format specifically designed for ultra-small mobile phones. Another great invention from SanDisk, the microSD is about a quarter of the size of an SD card and is the newest standard of SD flash memory specifically designed for use with ultra-small mobile phones and other devices. Like the miniSD, the microSD/TransFlash is ideal for use in storing media-rich files such as music, videos, and photographs in compatible mobile phones.Slot compatibility: TransFlash, or full size SD when used with the included SD adaptor.