It started with an idea for a credit card sized holder for MicroSD cards so I could carry them in my wallet. In the end it became a general purpose design for a flat storage holder for any number of SD/MircoSD cards, even added possibility of a keyring hole. The holder space is divided in 4 zones like:+---+-------+---+ |     |    1    |     | | 3 +-------+ 4  | |     |    2    |     |+---+-------+---+For each zone you can specify how many SD/MicroSD slots you want to add.The design comes with build in support that you have to remove after printing before you can use it. In the scad file there is a global variable 'Support' which you can set to false to not generate the build in support in case you have a better solution for support (like to hear about that) or use something like a powder printer that does not need the support.