MMC cards also come in a smaller form factor, of about half the size: 24mm x 16mm x 1.5mm. This alternate form factor is known as Reduced-Size Multi-Media Card, or RS-MMC, and was introduced in 2004. RS-MMC cards are simply smaller MMC cards; by using a simple mechanical adapter to elongate the card, an RS-MMC card can be used in any MMC (or SD) slot.
The only significant hardware licensor of RS-MMC cards is Nokia, who often uses RS-MMC in their Series 60 Symbian smartphones. Newer RS-MMC cards, used in Nokia's newer phones (like the Nokia 6630 and Nokia 6680), support a lower voltage (1.8 V instead of 3 V) mode to reduce battery demand, and these lower-voltage RS-MMC cards, known as Dual Voltage Reduced Size MMC, and can be marketed as MMCmobile when they meet the MMCmobile card standards. These low-voltage cards are backwards compatible with older RS-MMC devices. The dual voltage cards, and the MMCmobile are part of the MMC 4.x standards.