The OEM Huami has held its global launch for the second-gen Amazfit GTR and GTS wearables, although they will only be released in the US and UK markets to start off with. These smartwatches feature blood-oxygen, heart-rate, sleep and stress monitors, which are analyzed using their in-house PAI system. They will be available through channels such as Amazon on their release.
https://www.notebookcheck.net/Huami-launches-the-Amazfit-GTR-2-and-GTS-2-smartwatches-for-the-US-and-UK-markets.499579.0.html