R4 SDHC Description:

If you are familiar with R4 or any other flash card, setting up the R4SDHC is the same. The R4SDHC cartridge size is identical to that of the original R4DS cartridge. The microSD card is inserted through the top of the cartridge and fits flush with the cartridge. [R4 SDHC]

SanDisk MicroSD Transflash 2GB Description:

The SanDisk micro sd transFlash 2gb is about a quarter of the size of an SD card and is the newest standard of SD flash memory specifically designed for use with ultra-small mobile phones and other devices. Like the mini SD, the micro SD/ TransFlash is ideal for use in storing media-rich files such as music, videos, and photographs in compatible mobile phones.[SanDisk MicroSD]

What's included

1* R4 SDHC

1* SanDisk MicroSD 2GB card

Source: http://www.gameyeeeah.com/r4-sdhc-with-sandisk-microsd-transflash-2gb-p-1917.html