Rocky has this on his WIKI about this product:
http://www.geeetech.com/wiki/index.php/Arduino_SD_card_Module
But I don't understand it either! How could it do this??
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Break out board for standard SD card and Micro SD (TF) card
Contains a switch to select the flash card slot
Sits directly on a Arduino
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Ask them at:
http://www.geeetech.com/index.php?main_page=technical_support
Or email Rocky Himself at: Rockylou84@hotmail.com
I used to live close to these guys in Nanshan.