The Biostrap Total Health is a machine-learning powered wristband that uses a clinical-quality pulse oximeter to monitor heart rate, heart rate variability, oxygen saturation, respiratory rate, sleep patterns and activity.
Biostrap is different from other wearables in that it uses red and infrared light for readings rather than the usual green light. This allows it to penetrate deeper and measure HRV, oxygen saturation and respiratory rate. HRV is now being revered as a more accurate picture of overall health as compared to simple heart rate readings.
The strap syncs with their mobile app that gives you insights into how your body is working -- from the effect of coffee on your HRV, to what drinking can do to your night's rest.
It also has a 5 day battery life so you don't need to worry about charging it every night.