Meta has been working on over a dozen VR headset prototypes, but doesn’t want you to use any of them. That’s because these bulky “time machines,” as they’re called, aren’t aimed at consumers, but are in-house proofs of concept only for their in-house designers.

During a virtual roundtable last week, Meta CEO Mark Zuckerberg and members of Meta’s Reality Labs division demonstrated several of these prototypes. Many of them have their internal circuitry exposed, and some even look like you’re holding the entire contents of a desktop PC to your face – complete with extra-large fans and side handles to grip so your neck doesn’t snap under the weight.