First introduced at CES 2018 with a planned mid-year launch, Lenovo's Mirage Solo Daydream VR headset will land on May 11. The device features what is effectively a built-in smartphone to provide a completely untethered VR experience good for up to 7 hours per charge.
https://www.notebookcheck.net/Lenovo-Snapdragon-835-powered-Mirage-Solo-Daydream-VR-headset-coming-May-11.289360.0.html