Other watches have those features, too. (For example the Pixel Watch has both and I'm pretty sure recent Samsung watches do, too.)The exception is the recent Apple watches, I believe the series 4 and above have the ability to function as an ECG through a linked app and the series 6 watch has an oxygen monitor.
Thank you for clarifying this information @Bruce Stephens, its good to know there are others on the market too.Other watches have those features, too. (For example the Pixel Watch has both and I'm pretty sure recent Samsung watches do, too.)
Though be careful because that thread is mainly discussing purported blood glucose measuring watches, of which none of the things that are available and advertised as being able to measure blood glucose actually work at all.