The Yubikey 5 NFC and Yubikey 5C NFC have slightly different dimensions which is why there are two different designs. The Fusion 360 parameters can be adjusted to accommodate other models.
The cap fits on the key one direction with a slight round indentation on the cap to identify the side that covers the touch/button. This allows the cap to snap and hold onto the Yubikey. To remove the key from the cover, pull on the thin edges of the cover.
Both designs were printed with PETG. A brim was used (included in gcode file) to make sure the design did not move on the build plate. No supports are needed if the model is printed with the opening positioned on the build plate. Seams are aligned on the rear of the model.
Models identified with 5A fit the Yubikey 5 NFC.
Models identified with 5C fit the Yubikey 5C NFC.
The author marked this model as their own original creation.