A cast magnesium block holds all the optics and sensors, and is surprisingly hefty for an HMD. The VR headsets we've taken apart all used lightweight plastic.

But metal makes a better heat sink, and the electronics and IR illumination (likely VCSEL devices) all produce heat.

That pink stuff is a thermal pad to help transfer the IR rangefinder's heat into the aluminum frame.

Metal also offers a stiffer mounting place to keep the optics stable and focused after their rigorous calibration.

But stiff isn't always best—some of these components are mounted with foam adhesive, which will be more forgiving as things flex when heated.