Designed around zeropage's needle file handles, using 3mm needle files, case has a sliding top that is held in place with a friction fit.

F3D files included to edit as needed. Original design had a small bump under the lid to act as a latch, but turned out to be unnecessary in my case. Feature is suppressed in the Fusion file, but can be re-added if desired. I would suggest adjusting the shape if using, as the nub on my case broke on first use.