M2s are ultra-thin and removable storage cards that measure a mere 0.59 x 0.49 x 0.05 inches. It is the second smallest flash memory media, behind only microSD.

The company, which developed the format with Sony, will release it in 2 GB, 1 GB and 512 MB capacities, at a suggested retail price of $120, $55 and $45, respectively. It says a 2 GB M2 can hold up to 500 MP3s, 640 minutes of MPEG4 video or up to 4800 pictures.

microsSD cards, slots for which are becoming very popular in mobile handsets outside of the Sony Ericsson stable, top out at the same 2 GB capacity.

The new M2 cards are specifically compatible with Sony Ericsson's K610, K800, K790, M600/608, V630, W300, W710, W712, Z530, Z550, Z710, and Z712 mobile phones.

It includes an adapter for use with Memory Sick PRO Duo devices such as cameras and game modules, as well as additional Sony Ericsson phone models, including the he D750, K750, P910, P990, V800, W700, W800/810, W850, W900, and Z800.

SansDisk plans to release the M2 cards in January in most markets worldwide, with Japan availability following later in the quarter.