This item is for use with the #GridFinity system by Zach Freedman:
https://www.youtube.com/watch?v=ra_9zU-mnl8
A 1 wide by 2 deep by 1/2 unit high USB thumb drive and SD card holder for use on a weighted base plate.
UPDATE 2
As requested, I've added a USB only version with 8 slots to the archive. Please note they are angled due to the fact that the bodies of most USB drives are too wide to fit 2 columns/rows in parallel.
UPDATE I've added three additional STL files, one with a double height 10x Standard SD card version which is stack-able, a single height 10x Standard SD card version which is not and a half height 16x Micro SD card version which is stack-able. Please note that due to the depth required for the micro SD card and to keep the bin at half height the slots intersect with the screw holes on the bottom of the bin. You will be able to use magnets but not m3 screws.
Contrary to Zach's instructions, I've been printing all my modules with a 0.8 nozzle, which seems to work just fine. This item was printed with silver PLA at 75mm speed on an ender 3 pro with 0.8 nozzle and 0.32 layer height without support. The holder has slots for 4 USB Devices, 6 Standard SD cards and 6 Micro SD cards. The Standard slots are capable of holding 2 Memory Stick Duo's for all you PSP fans and even xD cards for you retro Fujifilm camera users. Tolerances are loose to allow the model to be printed easier on poorly configured printers that over extrude.