A crazy oblique view of the AKG K518. I put a "radiolucent" sponge between the earcups to hold the headband up. As you can see, the top headband is constructed out of steel! But everything else is plastic. That doesn't mean it lacks durability!
The folding mechanism seems to operate using multiple steel rods that act as pivot points. I should get some radiographs of the cans folded to see how they work.
Performed at 40kVp at 20mA at 1500ms.