This is a spool case for earbud headphones
Insert the earbuds in the spool, rotate the spool with your thumb to wind up the wire and then snap the cover shut.

There will likely be updates to this so it is listed as work in progress since ive yet to print out the latest adjustments to the hinge and snap close features.

12-26-2011: Increased Headphone Hole size in spool to accomodate a different pair of headphones. Decreased Slot size in outercase.

11-15-2011: Updated Outercase parts to increase hinge hole size and surrounding material slightly. Modified Snap feature on top of case to increase width and depth of snap tab(tab broke off rather quickly on last revision, hopefully this will help.)

(1) Print out the parts
(2) Snap the inner spool parts together. You may have to clean up the pins and holes on the two parts to get them to snap together. If your fit is loose you can use some super glue to keep them together.
(3) Align outer case parts together at the hinge point.
(4) Cut a piece of 1.75mm filament and install as hinge between outer case parts.Enlarge the hinge holes if necessary so the hinge joint is smooth.
(5) Superglue the filament to the bottom case if necessary to keep the filament in place
(6) Mount inner spool assembled earlier on the pin of the outer case. Do not use superglue on this pin joint as you want it to rotate freely.