T-Flash is the smallest removable Flash storage for mobile phones
"SanDisk T-Flash is currently the world's smallest removable flash memory storage format. It is similar in size and function to embedded flash memory but can also be readily removed and upgraded to allow for a range of memory capacities as well as interoperability with other consumer electronics devices. Approximately the size of a fingernail, T-Flash is designed for new mobile phones that are compact yet fully-featured with storage-intensive multimedia applications such as digital cameras, video capture and playback, MP3 players, video games, personal organizers, Multimedia Message Service (MMS), email and voicemail capabilities. "