This is like a giant pocket knife. You can open a "Blade" that holds the cards. Each SD card "Blade" holds 4 cards. The "Blade" for the Micro SD cards will hold up to 16 cards. You can stack from 1 to 8 "Blades". It has a positive lock to hold the "Blades" closed so it won't accidentally open and drop all your cards. You will need to use sheet metal or wood screws. The length is dependent on how thick the "Backbone" is. I used #4 screws. You will also need a 1/8" diameter brass or aluminum rod for the hinge pin. It needs to be about 1/8" longer than the thickness of the "Backbone".
The author hasn't provided the model origin yet.