microSD is a format for removable flash memory cards. SD is an acronym for Secure Digital. The cards are commonly used in cellular phones, as well as in handheld GPS devices, portable media players, digital audio players, expandable USB flash memory drives, Nintendo DS flashcards, and digital cameras.
It is the smallest memory card available commercially; at 15 mm × 11 mm × 1 mm (about the size of a fingernail), it is about a quarter the size of an SD card.[1] There are adapters which allow a microSD card to be used in devices intended for SD, miniSD, Memory Stick Duo and even USB cards. However, they are not universally compatible. Many microSD cards sold online and in stores are packaged with an SD adapter to use the card in devices that take SD cards. TransFlash and microSD cards are the same (each can be used in devices made for the other), except that microSD adds support for SDIO mode, enabling non-memory cards like Bluetooth, GPS, and Near Field Communication devices.[2]
A point ofin the microSD and the newer microSDHC format. The SD and SDHC share a similar form factor, but not all devices are compatible with the newer high capacity format. This is even true with devices that have been developed by SanDisk such as their e200 series of MP3 players. Using 3rd party firmware however, SDHC reading capabilities can be possible.[3]
microSD cards are available in capacities from 64 MB to 16 GB. A 12 GB version was developed by SanDisk but never released.[4] In February 2009 Sandisk also announced a 32 GB version for the second half of 2009,[5] but as per end December 2009 it is not listed yet. Almost all cards with sizes over 2 GB are SDHC cards although some early 4GB SD Cards are not classified as SDHC.
