Multimedia Card (MMC): MMC cards are available in three sizes, MMC/MMCplus that are about half as big as CF Card, RS-MMS/MMCmobile, and MMCmicro. The fourth generation cards can achieve write speeds of up to 7MB/s in theory. Due to their smaller sizes (24 x 18 x 1.4/1.1 mm), MMCmobile and MMCmicro cards are ideally suitable for mobile phones.
FOR: Very Small, comapatible with SD card slots.
Against: Limited memory capacity (max 4 GB).