To Our Customers:
The microSD format was created by SanDisk. It is the smallest memory card available commercially; at 15 × 11 × 1 mm (about the size of a fingernail), it is about a quarter the size of a standard-sized SD card. 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.
microSD cards with a memory capacity larger than 2 GB are microSDHC, which uses the exact same technology as SDHC, just in the smaller microSD size. The "HC" stands for "high capacity."