It’s called the Crescent Bay prototype, and it’s the follow-up to the current dev kit 2, which was dubbed Crystal Cove. The most immediate addition to this new prototype are the built-in headphones, which according to Oculus VR will add “high-quality” audio to the device.
In addition to adding headphones, Oculus has licensed software code by RealSpace3D. This technology has been developed over 10 years at the University of Maryland. When utilised by Oculus VR, the software will add “high-fidelity VR audio with a combination of HRTF [head-related-transfer function; basically how ears hear sound in a 3D space] spatialization and integrated reverberation algorithms” to the Oculus Rift experience.
In addition to the new integrated audio, the Crescent Bay prototype boasts new but unspecified display technology, full 360˚ head tracking (so presumably the camera can now track the back of the unit), and greater positional tracking. It’s also significantly lighter. Still no word on a consumer release date or when (if) this new prototype might be made available as a Dev Kit 3.