The side metallic part integrates the two major elements the user interacts with, and all in one piece:
1. The rails, for speaker height adjustment. The step pattern of the rails with the ball stoppers located in the speaker fixation insure a smooth yet stable interaction. This pattern was directly inspired from the ground metallic rails of the Stuttgart Porsche Museum.
2. The hinges, for a compact storage. Just like high-end glasses frames, this integrated spring loaded hinge allows a smooth "auto-lock" interaction while opening or closing the headphones.