
It is small sized memory card available at 15 mm × 11 mm × 1 mm. 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.
This can use for keeping MP3 songs, jpg images, vedios, small and largest sized files and etc. In early days, MicroSD cards are available in 16MB, 32MB format. But now, it can available in larger capacity then older. We can find out it now in capacities from 64MB from 2GB, where currently available from 4GB to 32GB and said out MicroSDHC instead of MicroSD.