This is actually a heavily redesigned box made into a somewhat functional speaker unit.

This is what you will get when you buy the non-3D printed parts. It'll include this speaker unit, cables and a pair of earpads.

It's designed for most 50-52mm drivers.

If you have not purchased this, then just ignore this page and go here:

Once you have received this, you should plug it in to test out to make sure all the parts work.
Disassembling the speaker will also show some ways as to how the headphones will be assembled along with how the wiring works.

The rectangular box is the original design. It was just overall kind of boring. And it would've still required extra parts to make sure the drivers fit snug and not shaking around within the box.

While the newer speaker box design looks better and more interesting while also functioning as a secondary project that you can work with rather than something to just immediately tossed out.

Start with one side of the shell as highlighted with the orange piece.

There are four screws securing the shell.

Remove the shell. The driver should sit in place.

Next, unplug the driver. Lightly pull on the driver to expose the connectors.

Repeat the same on the other side.

Now remove the two screws securing the middle piece.

Make sure you don't lose the two nuts on the back.

Next remove the 3.5mm jacks just using your fingers. If it's too tight, you can use needle nose pliers to loosen it up.

Remove the sockets one at a time.

All the parts needed for the headphones. And of course the cable and earcups.